New features:
- firenvim#eval_js() now takes a second optional argument which lets you
  specify the name of a callback function which should be called with
  the result of the evaluated expression (36a47bd, 748e516).
- It is now possible to ask Firenvim to ignore key presses, letting the
  browser handle them instead (dfccafd).
- Firenvim is now available for Thunderbird nightly (eed5303).

Bug fixes:
- firenvim#press_keys() now has keycodes in the events it generates.
  This means that press_keys() should work with non-standard compliant
  web pages (3040a83).
- The firenvim frame now has a lower z-index, allowing the Vimium frame
  to be on top of it.

Feature removal:
- The persistent server feature has been removed. It has been broken for
  a while and nobody complained.