Added SwarmingLogic icon, changed app name & id

Added SwarmingLogic icon, changed app name & id
Changed app name to "SWL Dev"
Changed app id to com.swarminglogic.swldev

This will make it easier to see what and how to change it to its final values.

    android/AndroidManifest.xml
    android/res/drawable-hdpi/ic_launcher.png
    android/res/drawable-mdpi/ic_launcher.png
    android/res/drawable-xhdpi/ic_launcher.png
    android/res/drawable-xxhdpi/ic_launcher.png
    android/res/values/strings.xml
    android/src/com/swarminglogic/swldev/SWLdev.java   (+)
Fixed Android mesh loading bug, unified

Fixed Android mesh loading bug, as it used regular file streams read the mesh
files. The CObjUtil has been renamed to ObjUtil and serves as the common
interface to load WavefrontOBJ files, whether that be compressed or not.

Since the common file reading interface lies in util/FileUtil, ObjUtil has been
moved from src/external to src/util, and the swl-util library now depends on
the swl-external library. This is fine.

TODO:
File loading can be further optimized by removing intermediary data
processing between FileUtil and extern/tiny_obj_loader. This should be tested
with -O3, and larger meshes.

    README.md
    src/SConscript
    src/SConscript_tests
    src/extern/CObjUtil.h     (-)
    src/graphics/Mesh.cpp
    src/graphics/Mesh.h
    src/extern/CObjUtil.cpp   -> src/util/ObjUtil.cpp
    src/util/ObjUtil.h        (+)
    src/extern/TestCObjUtil.h -> src/util/TestObjUtil.h