Docs: update driver installation details.

DRIVERS.md

@@ -28,6 +28,7 @@ access via the `Writer` and `CWriter` classes is documented
 
  1. [Introduction](./DRIVERS.md#1-introduction)  
   1.1 [Color handling](./DRIVERS.md#11-color-handling)  
+  1.2 [Installation](./DRIVERS.md#12-installation)
  2. [OLED displays](./DRIVERS.md#2-oled-displays)  
   2.1 [Drivers for SSD1351](./DRIVERS.md#21-drivers-for-ssd1351) Color OLEDs  
   2.2 [Drivers for SSD1331](./DRIVERS.md#22-drivers-for-ssd1331) Small color OLEDs  
@@ -127,6 +128,23 @@ application which uses the predefined colors. Differences become apparent when
 specifying custom colors. For detail see the main README
 [User defined colors](./README.md#311-user-defined-colors).
 
+## 1.2 Installation
+
+Please ensure that device firmware is up to date. On networked hardware a
+display driver may be installed as follows (example is for ST7789):
+```python
+>>> mip.install("github:peterhinch/micropython-nano-gui/drivers/st7789")
+```
+The last part of the addresss (`st7789`) is the name of the directory holding
+drivers for the display in use. In some cases the directory holds more than one
+driver: these will all be installed. Unused drivers may be deleted.
+
+On any hardware [mpremote](http://docs.micropython.org/en/latest/reference/mpremote.html#mpremote)
+may be used on the PC as follows:
+```bash
+$ mpremote mip install "github:peterhinch/micropython-nano-gui/drivers/st7789"
+```
+
 ###### [Contents](./DRIVERS.md#contents)
 
 # 2. OLED displays

README.md

@@ -187,7 +187,8 @@ This stuff is easier than you might think.
 
 ### 1.3.1 Quick install
 
-This is done using the official
+On networked hardware this is done with `mip` which is included in recent
+firmware. On non-networked hardware this is done using the official
 [mpremote utility](http://docs.micropython.org/en/latest/reference/mpremote.html)
 which should be installed on the PC as described above.
 
@@ -217,8 +218,8 @@ $ mpremote cp color_setup.py :
 Installation is as per networked hardware except that `mip` on the target is
 replaced by `mpremote mip` on the PC:
 ```bash
-$ mpremote mip install("github:peterhinch/micropython-nano-gui")
-$ mpremote mip install("github:peterhinch/micropython-nano-gui/drivers/st7789")
+$ mpremote mip install "github:peterhinch/micropython-nano-gui"
+$ mpremote mip install "github:peterhinch/micropython-nano-gui/drivers/st7789"
 ```
 
 ## 1.4 A performance boost