Update libxkbcommon to 0.6.1.

libxkbcommon 0.6.1 - 2016-04-08
==================

- Add LICENSE to distributed files in tarball releases.

- Minor typo fix in xkb_keymap_get_as_string() documentation.

libxkbcommon 0.6.0 - 2016-03-16
==================

- If the XKB_CONFIG_ROOT environment variable is set, it is used as the XKB
  configuration root instead of the path determined at build time.

- Tests and benchmarks now build correctly on OSX.

- An XKB keymap provides a name for each key it defines.  Traditionally,
  these names are limited to at most 4 characters, and are thus somewhat
  obscure, but might still be useful (xkbcommon lifts the 4 character limit).

  The new functions xkb_keymap_key_get_name() and xkb_keymap_key_by_name()
  can be used to get the name of a key or find a key by name.  Note that
  a key may have aliases.

- Documentation improvements.

- New API:
  xkb_keymap_key_by_name()
  xkb_keymap_key_get_name()

(wiz)