Update AnalogOut pinname in the test
Added "supported_form_factors" list attr to targets which  defines TARGET_FF_* symbols for the supported form factors.
Unified some tests for targets that support Arduino form factor to use Arduino style pin names.
Merge branch 'master' of https://github.com/sg-/mbed
Added STM32 Dicscovery to README.md
Merge pull request #252 from dinau/change-readme

Added STM32 Dicscovery to README.md