Add support for object line colour and improve colour preferences

* Refactor into ILineObject
* Editor support for object line colour
* Makeover for Color Preferences
* Default colors are saved in model file
Use darker default line colour
Re-instate option to save user default colours and improve Format Painter

* Option to save user default colours in file re-instated
* Improve logic for what is a "default" user colour - depends on the Prefs option
* Improve Format Painter - can copy between connections and elements
Add support for default connection line colour in Preferences

* Also fix some bugs from before
Add option to derive element line colour from fill colour
[jaiguru] make bendpoint snap to grid (solve GEF issue)
[ArchiMate 2.1] Update Hints images of some Viewpoints
Merge branch 'line_color_prefs'
[Line Colours] Show hyperlink explaining why line colours are disabled
[Line Colours] Should not be disabled/hyperlink showing if this is a connection
[Preferences] More logical placement of some preferences
Set default Font name on Mac

* This now has a space in it
[Properties Controls] Better Color Selector

* Combined into one control
[Properties Controls] Better Font Selector

* Combined into one control
[Properties Controls] Better Text Alignment buttons
Merge branch 'improve_props_controls'
[jaiguru] make bendpoint snap to grid (solve GEF issue)
Update chnages.txt
[Model] Model elements should be Interfaces
Remove unused lines of code

* This was added by mistake