Should check for dirty git status and dirty git index as part of r2g test and r2g publish

[Alexander Mills]

Use these:

if  ! git diff --quiet; then
   echo 'Changes to files need to be committed. Check your git index.';
   exit 1;
fi

if  test `git status --porcelain | wc -l` != '0'; then
   echo 'Changes to (untracked) files need to be committed. Check your git index.';
   exit 1;
fi