Featurelevel improvments. Stuff that would be nice to have.

* add filtering support to Modelica Projects View

* add 'Link With Editor' support to Modelica Projects View

* add support for working sets to Modelica Projects View

* add standart toolbar (Back, Forward, Up, Collapse All, Link With Editor,
  'Filters/Working set menu) to Modelica Projects View
  
* add source code navigation support, you know, beeing able to click on
  stuff in the source code while holding down Ctrl
  (try it in JDT, best feature evah!)
  to do this more information from OMC needed
* implement quickfixes whenever possible, for this OMC needs to report
  error types
  
* right now if multiple modelica compiler plugins (plugins that define
  org.modelica.mdt.compiler extension) are available an error message is
  displayed and nothing works until exactly one compile is available.
  This can be changed to allowing user to configure which compiler to use on per 
  project basis. It's probably good to add a 'default compiler' setting also.
  
* if identical classnames exists in two files, strange things begin to happen
  in MDT. The user should be warned when this happens.