updating build settings to API 19
Merge branch 'develop' of github.com:Hybridity/android-gpuimage into develop
just leaving a note about edge strength
cleaning up Polka
renamed Sobel
Create GPUImageHalftoneFilter.java
Create GPUImageLuminanceThresholdFilter.java
changing filter parent class for Pulp
Created GPUImageMosaicFilter (unfinished)
renamed Sobel