Added information on building arm stmhal and teensy, including adding gcc-arm-none-eabi compilers

Getting-Started.md

@@ -140,3 +140,27 @@ At that point, you will have a functioning micropython executable, which may be
 
 ## Microcontrollers (Bare-Metal, without an OS)
 ### ARM-based microcontrollers
+On a Ubuntu 12.04LTS this worked 
+
+sudo apt-get remove binutils-arm-none-eabi gcc-arm-none-eabi
+sudo add-apt-repository ppa:terry.guo/gcc-arm-embedded
+sudo apt-get update
+sudo apt-get install gcc-arm-none-eabi
+(as of 2015Sept19 pulled in amd64 4.9.3.2015q2-1trusty1)
+
+If needed to remove 
+sudo apt-get remove gcc-arm-none-eabi
+
+Assuming the micropython has been installed in directory
+cd  stmhal
+make
+
+cd ../teensy
+sudo apt-get install realpath
+make
+(completes)
+See Running Scripts in https://github.com/micropython/micropython/wiki/Board-Teensy3.1)
+Discussion on design https://forum.pjrc.com/threads/24794-MicroPython-for-Teensy-3-1/)
+
+cd ../minimal
+make - FAILS