It was not quite clear how try_apply_alpha should behave if the given
color was not ALPHA_ONLY. The implementation just returned 'this'.
However, the build relied on it returning the given color.
This broke all bg and fg settings in the entire bar.
To clear this up, we switch this around take the alpha channel of 'this'
and also return 'this' if it isn't ALPHA_ONLY.
Fixes#2255
The intent is for every color to be stored in a rgba instance
The rgba class now stores the color in a 32 bit integer to save space
This also removes the unused class rgb and moves everything else into a
cpp file.
Many functions also had weird template parameters. For example
alpha_channel<unsigned short int> would give a 2 byte number with the
alpha channel byte in both bytes.
color_util::hex would return a hex string with alpha channel if unsigned
short int was given and without if unsigned char was given. Even more
curiously those parameters were passed to *_channel and the result
nevertheless truncated to 8bits.
