rmerge() now returns an updated status boolean

With the --push option toggled, the HEAD resulting from `scc merge` or `scc update-submodules` are only pushed to Github if this updated status is True.
Merge pull request #5 from sbesson/auto-submods

rmerge() now returns an updated status boolean
merge master -D org -I include -E conflict -E needs-fixes -E broken: PR 10 (Convert bash scripts to Python)
merge master -D org -I include -E conflict -E needs-fixes -E broken: PR 47 (Auto submod updating)
merge master -D org -I include -E conflict -E needs-fixes -E broken

Repository: openmicroscopy/snoopycrimecop
Already up-to-date.
Merged PRs:
  # PR 10 sbesson 'Convert bash scripts to Python'
  # PR 47 joshmoore 'Auto submod updating'
Conflicting PRs (not included):
  # PR 52 sbesson 'Filter improvement'

Generated by SCC-merge#144 (http://hudson.openmicroscopy.org.uk/job/SCC-merge/144/)