default colorspaces for exrs and jpegs
refactoring: moved colorspace related functions in a new file ColorSpace.cpp
new command line arguments : --inputspace and --outputspace to force the input and display colorspaces
now duke manage a file colorspace and a screen colorspace instead of a unique colorspace. It was not clear what the unique colorspace was refering to.
pass the colorspace command line arguments to the context.
Also added a test code to render only when the buffer is available, it will surely be removed in the next commits
rec709 color conversion functions
glsl bilinear and nearest neighbour filters
AlexaLogC to linear function is now correct
correct the type of the texture sampler for standard texture.
help for colorspace command line options
Merge pull request #38 from primefocusworld/pull_request_180913

Fixes #39 #40 #41 #42 Pull request 180913