Make classes public

Otherwise, they don't show up in the generated vapi file, thus can't be
used in unit tests.
Remove src/CMakeLists.txt
Remove test binary
TweetListEntry: Move to margin_right again
vimrc: Also ignore .lo files
tests: Add tweet length test
TweetUtils: Make calc_tweet_length public
tests/tweet_length: Add more test cases
vimrc: Ignore test-driver

Screws up my completion on te<tab>
tests/tweet-length: Add console output

Since vala(c) doesn't support all the g_assert macros, we need to print
the actual value ourselves.
Also shows that calc_tweet_length is broken for empty tweets.
tests: Add inline media downloader test
tests/tweet_length: Also print length for http test
tests/inlinemediadownloader: add get_media_path test case
Make more functions/classes public
TweetUtil: Fix the empty text case in calc_tweet_length
main-window.ui: Don't set the icon name
Filter: Correctly implement matches()
Correctly filter tweets
assets/CMakeLists: Don't install the filter symbolic twice
Remove old symbolic icon