Implement Health Status view, fixes #306
Pascal's feedback, perfs improvements
fix tests
Merge pull request #354 from TheoChevalier/health-status-view

Health status view
import VCS classes explicitely (documents the use of a dependency in the model)
copying Project:: in a temp variable is not improving readability
ignore en-US completely
use anonymous function in loop to avoid code repetition (DRY) and suppress temporary  variable
remove unused variables + indentation fixes
ignore entities that are empty in en-US and for the locale too
merge unsets + formatting/comments nits
remove unnecessary unsets + temp variable + comment nit
remove empty entities early in the process, use lambda function for filtering
remove useless temp variable + indenting fix
Merge pull request #355 from pascalchevrel/locale_dashboard_view

Locale dashboard view
Revert "Locale dashboard view"
Merge pull request #356 from mozfr/revert-355-locale_dashboard_view

Revert "Locale dashboard view"
Don't hardcode Gaia versions in bash scripts and PHP
Merge pull request #362 from flodolo/version_management

Stop hard-coding Gaia versions