Also made some floating-point math more explicit

Improved commenting in dsp.c
Updated copyright notices
Code tidy up in some parts

Now RGB based instead of HSV based, this also includes a new RGBA compositing function which cleans up the code responsible false color significantly.

Color palettes have also been moved into 1 file instead of 2

This fixes the build.  It looks like the tree was forked during
some incomplete work :(

new dsp code
ngvi test

-new resample filter
-accept different sampling rates

change -s option

remove bogus 16bit mode
simplify false color computation
clean and indent code