Documentation update

* Added missing documentation on use of Smeter / Power-meter
    display on main dialog.
  * Added new xmlrpc TxID commands

fldigi_doxygen/user_src_docs/TransceiverControl.txt

@@ -76,6 +76,14 @@ then entering the numeric value in KHz.  Don't forget the decimal
 point if you are entering a fractional KHz value.
 <br>
 
+The Smeter / Power-meter display is only active if fldigi is configured for xmlrpc
+control with flrig.  The transceiver must support the smeter and power out CAT query.
+fldigi does not try to estimate the smeter reading based on the audio stream.
+You can toggle viewing the Smeter / Power-meter display using the View menu item
+"View/Hide Smeter."  Be sure to save the configuration for this to persist the next
+time fldigi is executed.
+<br>
+
 The mode combobox, the bandwidth combobox and the frequency display
 also annunciate the current transceiver status.  If you change
 operating mode on the transceiver, that will be annunciated in the

fldigi_doxygen/user_src_docs/xmlrpc-control.txt

@@ -119,6 +119,7 @@ main.get_lock              | b:n | Returns the Transmit Lock state
 main.get_max_macro_id      | i:n | Returns the maximum macro ID number
 main.get_reverse           | b:n | Returns the Reverse Sideband state
 main.get_rsid              | b:n | Returns the RSID state
+main.get_txid              | b:n | Returns the TxRSID state
 main.get_squelch           | b:n | Returns the squelch state
 main.get_squelch_level     | d:n | Returns the squelch level
 main.get_status1           | s:n | Returns the contents of the first status field (typically s/n)
@@ -138,6 +139,7 @@ main.set_frequency         | d:d | Sets the RF carrier frequency. Returns the ol
 main.set_lock              | b:b | Sets the Transmit Lock state. Returns the old state
 main.set_reverse           | b:b | Sets the Reverse Sideband state. Returns the old state
 main.set_rsid              | b:b | Sets the RSID state. Returns the old state
+mmain.set_txid             | b:b | Sets the TxRSID state. Returns the old state
 main.set_squelch           | b:b | Sets the squelch state. Returns the old state
 main.set_squelch_level     | d:d | Sets the squelch level. Returns the old level
 main.set_wf_sideband       | n:s | Sets the waterfall sideband to USB or LSB
@@ -145,6 +147,7 @@ main.toggle_afc            | b:n | Toggles the AFC state. Returns the new state
 main.toggle_lock           | b:n | Toggles the Transmit Lock state. Returns the new state
 main.toggle_reverse        | b:n | Toggles the Reverse Sideband state. Returns the new state
 main.toggle_rsid           | b:n | Toggles the RSID state. Returns the new state
+main.toggle_txid           | b:n | Toggles the TxRSID state. Returns the new state
 main.toggle_squelch        | b:n | Toggles the squelch state. Returns the new state
 main.tune                  | n:n | Tunes
 main.tx                    | n:n | Transmits