* Fix post-process shader when not in Vulkan
The post-process shader must not flip the source texture when we compile for OpenGL. This happens because we use SPIR-V/Vulkan as an intermediate format.
* Fix the Android build
We need to output a location when targeting SPIR-V for mobile.
* Update build instructions
* Compile shaders in a separate static library
Each shader string is now part of a separate .o file, which should make recompiling filamat/matc a tad more enjoyable.
* Shaders.h belongs to filamat, not filament
When compiling with clang on Linux, the following warning is generated:
../../libs/image/src/ImageDecoder.cpp:487:13: warning: unterminated '#pragma pack (push, ...)' at end of file [-Wpragma-pack]
#pragma pack(push, 1)
^
According to [1], the correct pragma to pop the packing state from the
internal stack is "#pragma pack(pop)" rather than "#pragma pop()" which
is used currently. This commit replaces "#pragma pop()" with "#pragma
pack(pop)".
[1] http://gcc.gnu.org/onlinedocs/gcc-4.2.3/gcc/Structure_002dPacking-Pragmas.html
