core: const correctness

This commit chanages several functions in renderdoc/core to const functions.
Merge pull request #51 from zerhacken/minor-fixes

core: const correctness
jpeg compressor: fix VC++ warning C4703

This commit fixes VC++ warning C4703 in jpeg-compressor/jpgd.cpp
"potentially uninitialized local pointer variable".
core: fix VC++ warning C4703

This commit fixes VC++ warning C4703 in core/remote_access.cpp
"potentially uninitialized local pointer variable".
Merge pull request #52 from zerhacken/vs2013-compiler-warnings

vs2013 compiler warnings
check for vshost exe as well as other exes to detect replay app
Don't call thread exception handlers on mono that aren't implemented yet