Don't install Linux-only content when compiling with MinGW
Remove colorhug-inhx32-to-bin and move functionality into colorhug-cmd
Remove the experimental and not-yet-installed colorhug-spectro-util

This was only ever hacked together, and when we do CH+ we'll have some nice
*designed* applications rather than just the debugging interface.
trivial: Split out a function which may be useful later
trivial: Fix up some lint spotted by the release tools
Release version 0.2.4