fixes install target, adds travis badge, invokes make test

edit README.md
 * adds travis status badge

edit Makefile
 * fixes install target to depend on youtube-dl.fish
 * fixes README.md target to invoke youtube_dl compliant with python-2.6

edit .travis.yml
 * adds pre-install verbosity
 * pandoc installation
 * make, make test, sudo make install,
It's rare to see sudo in invocations. Note that this is incorrect if the target directory is in the user's home directory, and thus not necessarily writable for root.