Removed naming path and i18n from project

- Replaced all occurances of 'path' to 'namespace' to follow new
handlebars statements
- Replaced all occurances in the routes from '/i18n' to
'/translate.me'. To open the admin ui, use '/translate.me/admin'
- Replaced naming of Database class to TranslationStore to make it more
generic. To override the default TranslationStore, just set the
property translationStore of an TranslateMe object. This might be used
in the future, to enable proper unit tests.
- Fixed bug which removed the namespace in the HandlebarsParser in some
circumstances
- Improved sorting in the admin ui