Modify resetStopOnReset to use vector catch

Modify the function resetStopOnReset to use the vector catch instead
of a breakpoint.   This allows flashing to succeeded on blank parts
with an invalid reset address in the vector table.  This also frees up
an extra breakpoint during the flash sequence.

This commit also remove the redundant reset in the
function setTargetState.
Update README.md with new changes

Update basic_test.py and gdb information in README.md.
added improvements to readme file
Merge pull request #71 from c1728p9/master

Update readme and use vector catch for resetStopOnReset for cortex m
Merge pull request #72 from mbedmicro/readmeUpdate

Readme: improvements to readme file (python 2.7, test basic script,