Added tool for merging site translations

Adds a tool that takes 3 files, the original english strings file,
the current version of a specific language strings file and a
file containing all the new strings for that language. It then
parses all the files and merges the third file with the second.
Needs an update to merge new strings. Part of #740
Add support for new strings to mergeTranslation.py

If a new string is encountered in the translated file it will
now add it to the original language file. Part of #740