Prevent flash security check from locking target

The function checkSecurityBits returns 0 when the flash settings would
lock the target processor.  This in turn causes programPage to return
without programming the current page.  The problem with this is
on Kinetis processors, if the security byte is erased it will lock the
part.

This patch renames checkSecurityBits to overrideSecurityBits.  Data
to be flashed is passed into this function which modifies the security
bits to a safe value, and then returns the new data.
Add resume parameter to Board.uninit

When uninitializing a board, it is not always desirable to let the
processor run.  This patch adds the parameter 'resume' to Board.uninit.
This allows the calling script to uninitialize the board without
letting it run.  This is useful if you want to keep the board halted
when running a series of scripts.
Add software reset to Cortex M processors

Add an optional software reset parameter to the functions reset and
resetStopOnReset.
Merge pull request #61 from c1728p9/master

Reset - add resume parameter and add software reset, Kinetis - flash security method protect a device from locking