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.

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.

Passes are flipped when northbound, not southbound

Lack of clamping while reading a pixel from a palette resulted in reading invalid memory

Checking if the type string contains paletted instead of just the current image
leading to palettes attempting to be applied to images without a color buffer

Creating a paletted image along with other images broke it

I will tidy this up in the next few commits

Processing more than one image at once didn't work (quite bodgey)
MCIR would run even without a map
Error handling for map/raw images that don't exist

Allows custom filenames for the output image
Fix formatting in help text

Also improve land color in MCIR images

Add linear equalise
Add image flip for southbound passes
Completly remove old falseclor in favour of a much simplier method

Change calibration to better suit constant gain
Add -Wextra to Makefile
Add link to model of the PLL
Max number of rows for the image is now increasible

Also change palette to something nicer

Add a denoise filter
Fix temperature calibration
Tidy up some files
Improve MCIR