Add test for version output file
Move to the folder contraining the version file before calling git describe

This commit should fix #122 by ensuring the git describe command is called
from the folder containing RELEASE-VERSION. This should prevent `git describe`
to read the version from another Git repository and overwrite the scc version.
Merge pull request #124 from sbesson/testconfig

Drop TestGithub from TestConfig integration tests
Merge pull request #123 from bpindelski/whitespace

Fix whitespace in conflict message.
Add tests for RELEASE-VERSION file existence

- Rename existing RELEASE-VERSION at the beginning of test and restore it
at the end
- Check RELEASE-VERSION does not exist before running version tests
- Check RELEASE-VERSION is created before opening it
ADd unit test for version file overwriting
Add test for `scc version` command outside a Git repository
Use abspath when computing version_file location
Add failing test for new label parsing functionality
Add logic to parse PR description/comments for labels

With this commit, if any line starts with "--label ", the following content
will be treated as label and used for exclusion/inclusion.
Add integration test for label added to the PR description
merge master -D org -I include -E exclude: PR 122 (scc version is overwritten when called from a Git repository)
merge master -D org -I include -E exclude: PR 125 (Teach `scc merge` to parse comments for labels)