Fix Drag and Drop when Droppable is behind an invisible element

When a Draggable is being dropped all elements below the Draggable are
checked for being Droppables. This process didn't work correctly when an
invisible element was above the Droppable.
Fixed the static import bug.
Also did some work to highlight the selected tab button.
For some reason this doesn't work right though.
#3466470: fromXml method swallows exceptions, preventing shutdown

throws RuntimeException now instead of only calling e.printStacktrace()
Merge branch '1.3' of ssh://nifty-gui.git.sourceforge.net/gitroot/nifty-gui/nifty into 1.3
#3474253: Blur.Multiply effect in scrollpanel default style

wrong backgroundColor for the background of the scrollpanel made the
scroll content to be displayed a bit dark
Slick2D-Renderer: Added missing comments, removed some useless ; and made parts of the code easier.
General code refactoring
- Removed obsolete parts of the code
- Improved documentation, removed useless documentation
- Reformatted code
- Removed a few potential bugs
- Fixed method visibilities
- Fixed names of variables to avoid shadowing
- Added a few annotations and comments to control the inspection of IntelliJ
- Removed unnecessary control flow statements
- Removed magic numbers
- Added initial size to lists
- Widend use of classes where possible
- Narrowed local variables
#3483275: Wrapping spaces inconsistency [fix included]

Applied a patch from tumaini to improve the TextBreak class
Slick2D-Renderer: Implementing additional functions to request exclusive access on input events
Slick2D-Renderer: Fixed some bugs that occurred in case the inline color changing was used
Merge branch '1.3' of https://github.com/mkaring/nifty-gui.git into 1.3
Merge branch '1.3' of git://github.com/void256/nifty-gui.git into 1.3
Slick2D-Renderer: Allow to change the default size of the UnicodeFontLoader and the TrueTypeFontLoader.
Slick2D-Renderer: Implemented methods to control the rendering and update order of the Nifty-GUI and the game.
Merge pull request #11 from mkaring/1.3

Slick-Renderer Updates
#3497744: Draggable freezes if dragged outside scroll panel

This was a problem related to the childClip property of an element. Any
element that is a child of an element with childClip set to true (so
that this element is being clipped to it's parents area) will take the
parent area into account when being checked for mouse events. So that
mouse events that are inside of the element but outside of the parent
clipping region will not be reported as "hits" for the element.

This is the correct behaviour. Unfortunatly the parentClipArea was not
reset when a drag operation started. So we end up with a draggable that
can be dragged but when being dropped will keep the parentClipArea of
it's original parent :) The result is that mouse events (as the mouse
button release event in case of the dragStop() operation) will never be
reported to the draggable - because the events occur outside of the
parentClipArea =D

This is now fixed: If elements change its parent element using
setParent() or with nifty.moveElement() the parentClipArea attribute of
the new parent are used for the element. So when you drag an element
from within an element with parentClipArea enabled the parentClipArea of
the dragged element will be disabled (because the new temporary parent
of the element, the popup, does not have parentClipArea set). This way
the dragStop() event is being called correctly and this problem is
fixed.

On the other hand if you drop the draggable on a droppable with
childClip set the parentClipArea of the new parent will be used for the
draggable as well. So this is actually two fixes in one ;)
Merge branch '1.3' of github.com:void256/nifty-gui into 1.3
Slick2D-Renderer: Fixed switched parameters at angelcode font loading. Bug report: 3493644
#3502523: Cannot remove screen controllers

Applied a patch by Tim B (timboura) that allows removal of
registered ScreenControllers. Be careful do not remove a
ScreenController that is still in use when calling 
unregisterScreenController() :) This is not checked at the moment!
#3489432: Better Loggernames

We now make sure there are now top level logger names. All loggers are
now using the Nifty package.