Remove path checking from get_cygwin_path

`get_cygwin_path` now does not check that the path exists, since this is not required by `cygpath`. Job is now responsible for checking that target exists. Missing target now raises `TargetNotFoundError`. Fixes #28.
Merge branch 'release_1.0' of github.com:jeinarsson/josync into release_1.0
Merge branch 'develop' into release_1.0

Conflicts:
	josync.py
change notification success tag file to reside at the same place as the job file