New regression, only linear as per recommendation of the Users' Guide

Exported functions and types prefixed with apt_
  Callback added for getsample, instead of calling named function.
  Allow library to be built without libpng or libsndfile.
Add support for building with MSVC on Windows.
Fix a few MSVC compiler warnings.
Fix nonlinear radiance correction for NOAA19.

The crop noise effect shifts the enetire image in memory, however when applying a map this shift did not get taken into account.

Don't try to memcopy into a null pointer

Was opening PNG files (which are binary...) with `r` instead of `rb` which caused problems on windows
Added `libsndfile-1` back into FindLibSndFile.cmake, since it's needed
Package `sndfile.dll` instead of `libsndfile-1.dll` since thats what the binary looks for

Since release builds had -Werror on, every warning is counted as an error, and the #pragmas that supressed that warning caused a wrning them selfs.

It didn't even work in the latest commit

Create a copy of the image before modifying it for temperature calibration