Redmine

For some API use cases, it will certainly be helpful to find out which modules are enabled in a project. It is at least for a new feature we're developing at Planio. But in general, every API client which uses - let's say the issues API - should be able to check beforehand, if the issue tracking module is active in a particular project or not.

This patch adds enabled_modules to the projects#show API. They will be shown only if the include=enabled_modules URL parameter is used. The behaviour is exactly the same as for issue categories and trackers.

And while we're at it, it also makes the include=... URL parameters (for issue categories, trackers and enabled modules) available in the projects#index API.

Tests are included, only needs merging :)