v0.9.1

This release includes mainly improvements of the help (which was added in v0.9.0)
but also a few new keyboard shortcuts to copy information.
The help improvements also include an overlay showing keyboard shortcuts for the pressed key(s)
after pressing a key which is the beginning of a shortcut consisting of several keys to be pressed after one another.

Bugfixes:
- all shortcuts are listed in help
  commit 75a6c42c708e33e05c75b60f047e31ea34b7509e
  commit 239b3ec5b1e29af0f2c34bd20dc548ae01acdc7b
- up/down in help details
  commit 17925215feebe0b3fff727a75eba6fef5b7fcb1f
- don't treat window resize as key press
  commit 3e423d0c8edb04299b35e95ab7024a7b1015a769
- yank: list all wildcards in help; id and cwd can be embedded in longer strings
  commit 5b208bb17c24b71110011e81f8b0ab52a9648583
- yank --clipboard did not copy to clipboard
  commit 223a8b845e340f6f3c0fc4c4795cb6f32d9738ef
- don't claim undefined commands were primitive commands in help
  commit ea5e08afb6d4158fe1c411ae52e4f1cdbd22e6f9
- don't crash in case a certain internal error would occur
  commit 8a81c40e5e3338a53ee5db744bcedf99cf2c36f3
- align shortcut list
  commit 662bb00fe06a994e0da6bfe7184d47c4403068e9

Changes:
- renamed "gitu specific commands" to "programmable commands"
  and "urwid commands" to "primitive commands"
  because "cancel" is not contained in the standard urwid.command_map values.
  I chose the name "primitive" in reference to TeX.
  commit c952d7b7334b5826470d2ed3ad851540e5465d44
- key format
  commit 620609f5acc3f0327ceb4453d37f3a20b90bbf28
- changed colors
  commit 017c533ef7dce6b41ff1b6e77dcb72734fb37594
  commit 233f0c0d659f94098d99869560a24b3f61451466
- colors for keys and commands
  commit 90718c1d13f258309007f41e680ef17709f75a45
- how keyboard shortcuts are sorted
  commit bd9a52094aeba5b5b85a0f4fa541a88e0ac52663
- highlight sections in help view
  commit a6f1a4829e500c38f9e95bb48a8866cdeec5c8e1
- help details: added prefix "command"
  commit e17edbb654b3c514df445133fd22858b15094f8f
- help: replace newline and tab characters in command
  commit 9e42831d623f1b67594f83dbb3ba23aa9e5debad

New features:
- fallback commands
  commit 75a6c42c708e33e05c75b60f047e31ea34b7509e
- pressed keys overlay
  commit a4d3c757bdb2e9e51989b6ab0b411a9cca7d3d14

- yank: new wildcard "type"
  new shortcut to copy object type (yT)
  new shortcut to copy "bugfix for <object type> <hash id>" (yr)
  commit 09679ed3513596bdd1c7bcf9f2a647c5e6fc6f0b
  commit 60f7b063fef74001fbc7ba48c91354e26f57136e
- new shortcut to yank committer and author environment variables (yE)
  commit 62089400548f0c448a2ff0a48fc84cc78008be88
- new shortcut to clear clipboard (yx)
  commit fd862c165607436f7cdb73ef2c9d3f9b7b671422
- yp and yx work on unstaged and uncommitted changes, too
  commit ef3371be23a17785c4c81b4b0a73db8ff2dae63c

- help: primitive commands vs programmable commands
  commit c952d7b7334b5826470d2ed3ad851540e5465d44
- search help: settings and flags
  commit 575023e7d334c44763fc0716ff53f03da6a16857
- search help: regex
  commit ddb2a1c8a2825f2b147bedf7c4159f1e20da5db8