Remove merge_all script

Use scc update-submodules instead
Refactor prep.sh to allow more control using environment variables
Remove hard-coded Python paths in the doc generation scripts
Add logic to symlink BIOFORMATS artifacts during release script
Update sha1 of 4.4.6 documentation to make local test pass
Unify use of SNAPSHOT_PATH envvar across scripts
Add SNPASHOT_URL environment variable
Use new SNPASHOT_PATH environment variable
Generate snapshot structure if not present
Fix relative link in bfgen.py
Display whole path in exception for debugging purposes
Fix missing slashes
Merge pull request #1 from sbesson/jenkins_release_job

Jenkins release job