More comments added to methods in host_test.py
Host test: wrapped mbed.serial.timeout into separate function to avoid traceback and send proper IO_SERIAL error from host test(s)
Bugfix: when displaying extra summary using -t option some indexes are not found and dictionary must be checked against key
Removed DISCO_F407VG from the official build

It was basically useless, since there's no corresponding target on
mbed.org
Merge branch 'master' of github.com:mbedmicro/mbed
Fixed toolchain colummn order when using --config option
Removed two logger entries in global test api functions (JSON parser prompters)