Revert status output to a single prompt element

Output for changes staged/unstaged/unmerged/untracked are combined to a
single prompt element %{status}, like it was prior to the recent rewrite
(though it used to be called 'changes').

The main reason for this is to address script performance.  The sed
calls in prepare_element start to add up, and having fewer of them helps
improve runtimes.  The ability to customize the prompt via a flexible
format string is a really nice feature that I'd like to keep, so I'm
reducing the number of substitutable elements in an effort to balance
performance.  Reverting this specific change is one of the easier
decisions to make in that regard.

Furthermore, the actual element_status implementation is updated to rely
on fewer external calls, additionally aiding performance.

Now that the output is controlled by a single element, the arrangement
of the different change stages is no longer fine-tunable via the prompt
format string.  A fixed order is produced: staged, unmerged, unstaged,
untracked - exactly as it was before the recent rewrite.  Within the
output, these stages are separated by a "status separator" string (as
before), however this separator is now exposed to the user as a
configurable environment variable.

Signed-off-by: Matt Hunter <m@lfurio.us>

0 files changed, 0 insertions, 0 deletions