Update plugin-api.md

Couple of clarifications, and fixes to minor errors.

docs/software/plugin-api.md

@@ -15,10 +15,10 @@ Packets can be sent/received either as raw binary structures or as [Protobufs](h
 The relevant bits of the class heirarchy are as follows
 
 * [MeshPlugin](/src/mesh/MeshPlugin.h) (in src/mesh/MeshPlugin.h) - you probably don't want to use this baseclass directly
-  * [SinglePortPlugin](/src/mesh/SinglePortPlugin.h) (in src/mesh/SinglePortPlugin.h) - for plugins that receive from a single port number (the normal case)
-    * [ProtobufPlugin](/src/mesh/ProtobufPlugin.h) (in src/mesh/ProtobufPlugin.h) - for plugins that are sending/receiving a single particular Protobuf type.  Inherit from this if you are using protocol buffers in your plugin.
+  * [SinglePortPlugin](/src/mesh/SinglePortPlugin.h) (in src/mesh/SinglePortPlugin.h) - for plugins that send/receive from a single port number (the normal case)
+    * [ProtobufPlugin](/src/mesh/ProtobufPlugin.h) (in src/mesh/ProtobufPlugin.h) - for plugins that send/receive a single particular Protobuf type.  Inherit from this if you are using protocol buffers in your plugin.
 
-You will typically want to inherit from either SinglePortPlugin (if you are just sending raw bytes) or ProtobufPlugin (if you are sending protobufs).  You'll implement your own handleReceived/handleReceivedProtobuf - probably based on the example code.
+You will typically want to inherit from either SinglePortPlugin (if you are just sending/receiving raw bytes) or ProtobufPlugin (if you are sending/receiving protobufs).  You'll implement your own handleReceived/handleReceivedProtobuf - probably based on the example code.
 
 If your plugin needs to perform any operations at startup you can override and implement the setup() method to run your code.
 
@@ -45,9 +45,9 @@ A number of [key services](/src/plugins) are implemented using the plugin API, t
 The easiest way to get started is:
 
 * [Build and install](build-instructions.md) the standard codebase from github.
-* Copy [src/plugins/ReplyPlugin.*](/src/plugins/ReplyPlugin.cpp) into src/plugins/YourPlugin.*.  Then change the port number from REPLY_APP to PRIVATE_APP.
+* Copy [src/plugins/ReplyPlugin.*](/src/plugins/ReplyPlugin.cpp) into src/plugins/YourPlugin.*.  Then change the port number from *PortNum_REPLY_APP* to *PortNum_PRIVATE_APP*.
 * Rebuild with your new messaging goodness and install on the device
-* Use the [meshtastic commandline tool](https://github.com/meshtastic/Meshtastic-python) to send a packet to your board "meshtastic --dest 1234 --ping"
+* Use the [meshtastic commandline tool](https://github.com/meshtastic/Meshtastic-python) to send a packet to your board, for example "*meshtastic --dest 1234 --sendping*", where *1234* is another mesh node to send the ping to.
 
 ## Threading
 
@@ -60,10 +60,10 @@ For any new 'apps' that run on the device or via sister apps on phones/PCs they
 
 If you are making a new app using meshtastic, please send in a pull request to add your 'portnum' to [the master list](https://github.com/meshtastic/Meshtastic-protobufs/blob/master/portnums.proto).  PortNums should be assigned in the following range:
 
-* 0-63 Core Meshtastic use, do not use for third party apps
-* 64-127 Registered 3rd party apps, send in a pull request that adds a new entry to portnums.proto to register your application
-* 256-511 Use one of these portnums for your private applications that you don't want to register publically
-* 1024-66559 Are reserved for use by IP tunneling (see FIXME for more information)
+* **0-63** Core Meshtastic use; do not use for third party apps
+* **64-127** Registered 3rd party apps.  Send in a pull request that adds a new entry to portnums.proto to register your application
+* **256-511** Use one of these portnums for your private applications that you don't want to register publically
+* **1024-66559** Are reserved for use by IP tunneling (see *FIXME* for more information)
 
 All other values are reserved.
 
@@ -73,4 +73,4 @@ If you would like to use protocol buffers to define the structures you send over
 
 * Create a new .proto file in the protos directory.  You can use the existing [remote_hardware.proto](https://github.com/meshtastic/Meshtastic-protobufs/blob/master/remote_hardware.proto) file as an example.
 * Run "bin/regen-protos.sh" to regenerate the C code for accessing the protocol buffers.  If you don't have the required nanopb tool, follow the instructions printed by the script to get it.
-* Done!  You can now use your new protobuf just like any of the existing protobufs in meshtastic.
+* Done!  You can now use your new protobuf just like any of the existing protobufs in meshtastic.