- Moved build.xml managed package version properties into external
  version.properties file
- Updated scripts/set_dependent_versions.py to update version.properties
  instead of build.xml
- Changed deployManagedUAT to fetch version.properties from GitHub for
  the tag and use the tag's version.properties instead of local repo's
  version.properties
Merge pull request #216 from SalesforceFoundation/feature/154-managed-beta-release

deployManagedUAT should use tag's managed package versions rather than local repo's