Merge pull request #3 from mbedmicro/master

Sync with master
Host test refactoring

Host test refactoring: replaced magic values of test results returned by host test

Prints with stdout.flush() replaced with notify function

Host test refactoring: created separate enum like class for test result strings
Merge pull request #577 from PrzemekWirkus/host_test-OO-refactoring

Tools: Host test refactoring - prepare to clean up host test implementation