Merge branch 'options' into working

Conflicts:
	mfloop.py
Merge branch 'master' of github.com:MarkRose/primetools
Merge branch 'options'
Merge branch 'options'
Merge branch 'options'
Enable not falling back to mersenne.org when gpu72 fails.
Also take into account checkpoint files when buffering work by GHz-days.
Updated description of ghzd_cache command line option.
Make checkpoint file parsing compatible with mfakto.
Merge remote-tracking branch 'origin'

Conflicts:
	mfloop.py
Merge branch 'master' of github.com:MarkRose/primetools
Fix result submission issues by using POST.
Use new URL for login.
Merge branch 'master' of github.com:MarkRose/primetools
Work with new manual result submission response.
Merge pull request #4 from MarkRose/master

Fix to new submission page, use checkpoint files when calculating GHz-days