Support setting UI element colors without referencing Slick.Color

Add MAGENTA and CYAN to NUI Color.
Change formatting used for generating and parsing Slick.Color strings in GUI
Add getDisplaySize() to UIDisplayElement to remove lwjgl dependency
Merge pull request #822 from mkienenb/module-icon-registration

Allow modules to register icons
Merge pull request #826 from mkienenb/allow-gui-access-to-Display-size

Add getDisplaySize() to UIDisplayElement to remove lwjgl dependency
Merge pull request #824 from mkienenb/support-color-as-string-gui-methods

Support setting UI element colors without referencing Slick.Color
Change UIImage.setColor(String) to use ColorUtil method instead of buggy original code
Merge pull request #827 from mkienenb/update-UIImage-to-bug-free-color-parser

Change UIImage.setColor(String) to use ColorUtil method
Generated oak tree has now branches which connect to each other parts of the tree.
Refactored block dropping, so it allows dropping items (non-blocks) as well.
Systems can now dynamically inject new Components, prohibit adding of Components or modify Components for entities generated based on prefabs, effectively allowing to override/extend base behaviour.
Information about tool (item) used to destroy a block is now passed all the way down to the system that drops the items from destroyed block.
Added event that allows to modify the icon displayed in any inventory.
Making the component extending/overriding for entities generated from prefab actually work.
Modified how the growing Oak trees are built.
Restored default growing speed of trees.
Growing Oak trees are the only ones generated.
Work around for a framework bug - logging the error.
Trees grow only into replaceable block.
Revert the change.