Admino bugfixes pt. 4

_Commit messages copy-pasted_
 - Fixed overlapping of '...' and 'E' buttons on mac for asset refs in EC Editor
 - Moved the whole context menu handling from AssetTreeWidget to a new class 'AssetItemMenuHandler' to handle context menus of assets and asset storages outside of AssetTreeWidget i.e. SceneTreeWidget. #399
 - Load startup scripts by the order specified in config XML #567
 - Fixed a bug where upon deselecting item(s) with holding Ctrl + click, and then if space is pressed to check/uncheck the remaining selected items, the last deselected item was selected again #565
 - Added 'Display skeleton' attribute in EC_AnimationController to draw the skeleton #221
 - Ogre: Fix blue tinted shadows on windows when using the default rex/shadowcaster. Make Ogre render window startup parameters actually work, they need to be assigned as std::string not as int/bool (will produce empty string). If --antialias and --vsync not defined on startup check config value. Make more settings definable via config for OgreWorld::SetupShadows(). Add shadow texture FSAA setting.
 - ECEditor: Fix float types min/max limits so we can input bigger numbers via the UI than 999. Use QLocale::system().toFloat() to fix parsing errors on >999 number formatting. Fixes the bug in Transform, float, float2/3/4 and Quat.
 - A few typo fixes