Allow entities to have negative angles.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Selection guides.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Fixed a minor rendering issue and some of the problems with entity rotation and flipping.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Merge branch 'wxWidgets' of github.com:kduske/TrenchBroom into wxWidgets
Rotation fixes.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>
Entity decorators for rotation.

Signed-off-by: Kristian Duske <kristian.duske@gmail.com>