[mbed] Add K22F to build_release.py
Added GCC toolchain filter to the target list
Host test refactoring: cleaned a bit functionality of host tests. Forced test() function in DefaultTest to be method returning test result
Cleaned pyFlakes issues with unused imports
Minor style improvement
Merge pull request #586 from sg-/master

Tools: Add K22F to build_release.py
Merge pull request #588 from PrzemekWirkus/host_test_OO_refactoring_part2

Host test refactoring  - part2
Merge pull request #587 from EmBlocks/master

[export EB] GCC toolchain filter to supported target list.
Merge pull request #5 from mbedmicro/master

Sync with master