[PATCH 0/8] JSON-based search-mode

[Austin Clements]

This patch series replaces the text format parser used for search in
Emacs with a parser for the JSON format.  This should address the
escaping and flexibility problems that have plagued the text format.
Like the text format, it supports incremental output.

Patches 1-4 simply clean up the Emacs search code and could be pushed
before the rest of the series.  Patch 5 switches to the JSON plist
representation internally, but retains the text parser.  This requires
some changes to the text parser to keep things working, but don't get
too hung up on them since it's about to get replaced entirely.  Patch
6 adds a test.

Finally, patches 7 and 8 are the real meat.  Patch 7 introduces a
general incremental JSON parser.  For search, we could probably get
away with a simpler, hacky approach, but an incremental JSON parser is
the type of thing you only want to write once---hacky or not---and it
seems like the type of thing that could be useful elsewhere, too.
It's general enough to support things like incremental show buffer
rendering.

Patch 8 rewrites the search output parser to use the JSON format via
this incremental parser.