Combine Fields in the admin list view with field relations

• Resolved gh-287 that adds the feature to join/combine results of multiple fields in the admin list view.
• Update the tab string to make tabs dynamic in nature.
• Improved the compiler building of the admin list view
• Refactored the compiler list view body builder, in preparation of the relation fields.
• Added more options to the relation admin fields. gh-287
• Refactored the compiler update file method
• Updated compiler to allow dynamic update for language strings. Started adding the field relationship feature requested in gh-287