Adds support for the PP shaders in the Android UI.

Copies over the PP shaders to the APK's assets and installs them on run.
Exposes them via the video settings UI.

This is in anticipation of dropping the workaround for rotated blits on Adreno and instead forcing shader usage by the user.

Source/Android/res/values/strings.xml

@@ -157,6 +157,8 @@
     <string name="FSAA_descrip">Reduces the amount of aliasing caused by rasterizing 3D graphics. This makes the rendered picture look less blocky. Heavily decreases emulation speed and sometimes causes issues.</string>
     <string name="anisotropic_filtering">Anisotropic Filtering</string>
     <string name="anisotropic_filtering_descrip">Enhances visual quality of textures that are at oblique viewing angles. Might cause issues in a small number of games.</string>
+    <string name="postprocessing_shader">Post Processing Shader</string>
+    <string name="postprocessing_shader_descrip">Apply a post-processing effect after finishing a frame.</string>
     <string name="scaled_efb_copy">Scaled EFB Copy</string>
     <string name="scaled_efb_copy_descrip">Greatly increases quality of textures generated using render to texture effects. Raising the internal resolution will improve the effect of this setting. Slightly decreases performance and possibly causes issues (although unlikely).</string>
     <string name="per_pixel_lighting">Per-Pixel Lighting</string>