basic working independent inactive modified highlights.
use airline_c for better predicability.
check existence of inactive modified colors before using them.
fill in inactive modified colors.
show hidden buffers with a different color. resolves #229.
Merge branch 'master' into dev
implement customizable file name formatting (#230).
turn on deprecation warnings.
extract buffer name logic into a formatter.

hold off on deprecation warnings for now...
pass in buffers to the formatter.
keep fmod as a valid configuration variable.
minor cleanup of documentation.
Merge branch 'master' into dev