git: colourise git hist alias
scripts: add script to scrape from chromium/pepperflash
bash prompt: remove (now) unnecessary '_' varname prefixes
bash prompt: show when in git-annex enabled repo
bash prompt: strip the duplicated 'annex'

Regular indirect git-annex repos are labelled as normal repos,
e.g.

    user@host:~/music (master)

*direct* git-annex repos are lablled with a pseudo branch-name

    user@host:~/docs (annex/direct/master)

It's not a real branch, as `git branch` returns nothing. However, once
the git-annex disambiguation has been implemented in the PS1, it looks
like

    user@host:~/music (git-annex:master)
    user@host:~/docs (git-annex:annex/direct/master)

This commit turns the second into

    user@host:~/docs (git-annex:direct/master)

Limitations

  - It's a bit lazy, as now sed gets invoked on every prompt.
  - It may be an idea to change to 'git-annex|direct:master'
git: moved files; XDG_CONFIG_HOME now supported
git: set merge.tool in config
bash prompt: fixed not playing nice with etckeeper

  - etckeeper's sudo requirement prevents the bash prompt's
    examination. For now this has been bypassed if in /etc
scripts: a variable expansion fixed