Update gitignore structure.

Refactor out gitignore in /other/serialTest.
Add some more noticable headers.
Some simplifaction and restructuring.
Clean up some files.
Refactor out lib platform gitignore files.
Refactor out some gitignore files from AdvancedImageLoading.
Remove erroneously committed XCode project components. Closes #2057.
gitignore: correct comment spacing, minor updates.
feature add read-only access to current Matrix Stack

this is a clean PR and a replacement for PR #2479.

Original PR message:

having access to the matrix stack is really useful - the canonical example would be: if you want to push a normalMatrix to the shader (calculated once per frame on the CPU, used as a const many many times on the GPU):

	ofMatrix4x4 modelViewMatrix = ofGetGLProgrammableRenderer()->getCurrentMatrix(OF_MATRIX_MODELVIEW);
	ofMatrix4x4 normalMatrix = ofMatrix4x4::getTransposedOf(modelViewMatrix.getInverse());
	mShd1.setUniformMatrix4f("normalMatrix", normalMatrix);

Otherwise, you'd have to calculate the normal matrix in the vertex shader (per-vertex) or even in the fragment shader (per pixel!):

	mat4 normalMatrix = transpose(inverse(modelViewMatrix));

Matrix inverses are amongst the most costly GLSL operations.

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
add ofGetCurrentMatrix

* adds getCurrentMatrix to ofBaseRenderer and all its direct heirs

* adds ofGetCurrentMatrix which will return the current matrix state

* this will, in order not to over-optimise the code, return an ofMatrix4x4 by copy instead of a const ofMatrix4x4 & - I trust modern compilers will automatically move these things and find the code easier to optimise this way anyway.

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
add changelog entry

adds changelog entry for ofGetCurrentMatrix, since this affects core API

Signed-off-by: tgfrerer <tim@poniesandlight.co.uk>
use correct audio category for routing audio to speaker
closes #2100
changing releaseAll to clear bugs
ensuring that element is null
Merge pull request #2694 from tgfrerer/feature-get-current-matrix-state-GL-programmable

feature add read-only access to current Matrix Stack
Merge pull request #2718 from admsyn/fix-ios-audio-speaker-route

[ios] use correct audio category for routing audio to speaker
Android assets fix.
Zip file uses lowercase package name.
Doxygen config
Merge branch 'master' of github.com:openframeworks/openFrameworks
Merge pull request #2742 from falcon4ever/bugfix-android-assets

Android assets unzipping fix
On Windows/MinGW the value of $(PWD) is not always set to the correct "pwd" value.

In a few cases it is set to a Windows style path (C:\openFrameworks\apps\devApps\VboExample) instead of a Unix style (/c/openFrameworks/apps/devApps/VboExample) one. This results into errors when building the project and zipping the assets.
Merge pull request #2743 from falcon4ever/bugfix-android-projectpath

Android building script error when building from Windows
ofBaseApp: remove mouseReleased(void) - the variant with x/y/button params is always called anyway, so this one was essentially unused and confusing.

fixes #2668