Temporary quick and dirty rebase of stm32duino#61, Blinky with serial works on a maple mini (STLink upload, UART2).

Author: lacklustrlabs

Diff for: boards.txt

@@ -487,9 +487,9 @@ Disco.menu.xserial.third.build.xSerial=-DFIRST_THIRD_HWSERIAL
 Other.menu.xserial.enable_Serial=None
 Other.menu.xserial.enable_SerialAll=All
 Other.menu.xserial.enable_SerialAll.build.enable_Serialx=-DSERIAL_UART_INSTANCE=2 -DENABLE_SERIAL3
-Other.menu.xserial.enable_Serial2=Serial2 (if available)
+Other.menu.xserial.enable_Serial2=Serial2
 Other.menu.xserial.enable_Serial2.build.enable_Serialx=-DSERIAL_UART_INSTANCE=2
-Other.menu.xserial.enable_Serial3=Serial3 (if available)
+Other.menu.xserial.enable_Serial3=Serial3
 Other.menu.xserial.enable_Serial3.build.enable_Serialx=-DSERIAL_UART_INSTANCE=3
 
 # USB connectivity