Use a static table of tokens for agi::Path

The set of possible tokens is fixed, so using std::map is a bunch of
pointless overhead (that turns out to not even really simplify the
code).
Eliminate pointless runtime datastructures for CalltipProvider

And add some tests and make it actually work correctly.
Exclude the Windows-specific files from coveralls
Support passing a test filter to make test
Make the hotkey code a bit less bloated
Debloat and slightly speed up the MRU code
Clean up the json parser a little
Eliminate a pointless std::map in charset_conv
Store open dialogs in an unsorted vector

Even if every dialog in the program was open at once, linearly searching
a vector is quite fast enough.
Remove some cruft from the fonts collector
Fix SRT timestamp parsing
Clean up the SRT reader/writer a bit
Swallow spam from coveralls submission
Move AssTime to libaegisub and add tests
Add character counter tests
Add simple tests for agi::Split
Store hotkeys in a less dumb format
Remove unused test util functions
Update Indonesian translation
Slightly optimize AssDialogue serialization