tidying

In order to cope with high memory consumption, remove the 'rectangles…

…' member from OpenGLRenderer structure (liamg#152)

Changes to minimize memory allocations and to ensure OpenGL objects c…

…leanup (liamg#148)

Bug: mouse cursors leaks (liamg#136)

Fix changelog formatting

Add changelog to releases (liamg#126)

* Add changelog

* Add changelog

Fix broken API key

Switch to travis (liamg#125)

Fix newline at end of buffer issue (liamg#122)

* Fix newline at end of buffer issue

* Fix newline at end of buffer issue