This commit takes the existing travis task list and attempts to split
it into multiple jobs for the sake of efficiency. Also properly
separates out the build/deploy of documentation.
This commit enables travis to automatically build doxygen documentation
on updates to the master branch. The documentation is accessible from
the qTox website under the URL: https://qtox.github.io/doxygen
Allows for OSX packages through travis, .travis.yml requires editing
chore(travis): Let Travis deploy OSX
Allows Travis to start Deploying when ever a tag is applied.
Beside making it work again, there are some improvements:
Linux side:
* use minimal supported Qt version, currently it's 5.3
* use minimal supported GCC version, currently 4.8
* use newer ffmpeg version to compile against - 2.8.5
* compile qTox 2 times, first run without support for optional dependencies
* use ubuntu 14.04 for building (less deps needs to be compiled/added from PPAs)
OSX:
* add osx to build targets
