introduce new feature: BOOTLOADER_ABORTTIMEOUTONACT

When defined, the bootloader will abort the timeout when
it sees some activity (bootLoaderConditionSimple() or programming).
After aborting timeout, the bootloader falls back to conventional
exitting.

By default this feature is deactivated.
Activate it via the "DEFINES" varibale within Makefile.inc.
There add: -DCONFIG_HAVE__BOOTLOADER_ABORTTIMEOUTONACT

Signed-off-by: Stephan Baerwolf <stephan.baerwolf@tu-ilmenau.de>