fixes #679

bank = xAxis,heading =  yAxis, attitude = zAxis .
The rotation order is Y,Z,X; OpenFrameworks works in row Major so, the
Quaternion multiplication order is- xRotation * zRotation * yRotation.
added comment to specify rotation order
fixed for mouse registration issues with ofxGui.
issues included,
- ofxPanel was registering for mouse events 3 times on setup!
- ofxButton was registering for events in setup and registering again in the destructor.
- ofxSlider was never unregistering mouse events.

added mouse register and unregister methods to ofxBaseGui,
so all classes that extend ofxBaseGui add/remove mouse events via these method.

`registerMouseEvents()` and `unregisterMouseEvents()` have a flag which makes sure that no multiple mouse registration can be made.

`~ofxBaseGui()` destructor now unregisters mouse events for every `ofxBaseGui` object.
Merge pull request #2922 from julapy/ofxGui_mouse_listener_fixes

fixes for mouse registration issues with ofxGui
android: fix 32bits ndk path
ofGstUtils: unmap video frame to avoid leaks
PG bring uptodate with master
android: update projects to latest sdk
android examples: assimp and opencv, compile for arm7 only since the libraries are missing an x86 version
assimp and shader: reload gl resources when app is resumed
Android Shader Example Fix

Fix for #2825 as described by @micuat
https://github.com/openframeworks/openFrameworks/issues/2825
Merge pull request #2924 from danoli3/android-shader-example-fix

Android Shader Example Fix
updated CHANGELOG
Merge branch 'master' of github.com:openframeworks/openFrameworks
Merge pull request #2881 from Ahbee/bugfix-QuatToEuler

fixes #679
CHANGELOG: add quaternion changes