SpringMapEdit 1.4.0

This is the first official release from github and it brings major improvements to the SME platform, particularly targeting the GUI.

-SME now uses a single-window interface, which intelligently updates depending on what brushmode you have selected. Interface buttons also no longer steal input control from the main rendering area.

-Camera controls and orientation are greatly improved. You can now zoom in and out with the mousewheel, arrows always pan, and you can reset the camera to the default position/orientation using TAB. "L" is now bound to 'toggle mouselook', and mouselook using the middle mouse button also works much more intuitively than it used to.

-General lighting is much less dim and offensive to look at.

-Lots of bugfixes, basically every feature that is enabled should work correctly and intuitively.
-The terrain smoothing brush in particular should no longer be buggy and should give a much more intuitive response.
-The brush strength slider now changes its scale depending on what brushmode is selected (eg, height brushes use the map maxheight as max value, texture brushes use a scale of 100, etc)

Note: Features (as in trees and things) are currently disabled since the backend has not been cleaned up, does not work with newer model formats, and featuremaps should be replaced by featureplacer anyway.