Host test plugins: First draft with working pluging for mbed (serial sendBreak command for reset)
Host test plugins: Cleaned preliminary code before next round of refactoring and improvements
Host test plugins: Added license and fxed one parsing issue
Host test plugins: added return values to setup() and execute() interface methods
Host test plugins: moved serial port flashing just before plugin reset call
Host test plugins: added copy pligins, and removed Selenium and eACommander dependency from Test API
Host test plugins: Added MPS2 and Firfox copy methods (both not stable and require further development)

Host test plugins: Added 'stable' attribute to each plugin, by default all plugins are not stable

Moved all MPS2 related functions to MPS2 plugins in host test directory
Host test plugins: Added generic error printing to host test plugin base class
Host test plugins: removed unused pass statement
Merge branch 'host-test-plugin-improvements' of github.com:PrzemekWirkus/mbed into PrzemekWirkus-host-test-plugin-improvements

Conflicts:
	workspace_tools/host_tests/host_test.py
Merge branch 'PrzemekWirkus-host-test-plugin-improvements'