When the X-Icinga-Module-Enable header is send, the
modulemanager automatically tries to load javascript files for
that module. This is realized by adding the 'registerHeaderListener'
method to the async manager, which allows to listen to specific headers
and firing callbacks if a response with the specified header is retrieved.
Also the tests have changed a bit, requireNow should be used when using
the requiremock, so a require always loads files new.
refs #4092
refs #3753
QLinks can now define the target for their link. Additionally, the
targte 'body' is now always the <body> tag. This allows the
modulemanager to reload the whole page (with the navigation bar).
refs #4092
All JS Files now call 'requirejs' instead of 'require', also
the holder.js reference is removed and the history api added.
Tests are following in the next commit
refs #4303
refs #4315