Add a note about Ubuntu dependency packages

...which can be found in .travis.yml
Merge pull request #139 from khink/master

Add pointer to .travis.yml for Ubuntu dependency packages
redshift-gtk: Relay USR1 signal to redshift process

This also adds SIGINT to the signals handled by redshift-gtk.
Merge pull request #141 from jonls/relay-usr1-signal

redshift-gtk: Relay USR1 signal to redshift process
Makefile: Add README to distributed files

README was accidentally omitted from distribution, and the link from
README to README.md was missing since the file was renamed with the
Markdown extension.
contrib: Do not generate RPM spec

The RPM spec needs to be maintained manually anyway so it does not make
sense to autogenerate the file with the latest version number. This should
be done manually while updating dependencies and changelog.
systemtime: Use gettimeofday if POSIX timers not available
colorramp: Add float-typed colorramp_fill() equivalent
Add Quartz (OSX) gamma adjustment method
Add CoreLocation (OSX) location provider

Similarly to the Geoclue provider, the CoreLocation provider only
requests the location on startup.