This change adds two improvements to docs searching functionality.
First, search results will immediately be displayed when a ?search=searchterm
query string parameter is provided to any docs url.
Second, search results are now inserted into the browser history, allowing for
easier navigation between search results and docs pages.
Made temporary changes to include multiple keywords in rustdoc search
Implemented search based on multiple keywords
Added some commenting and house cleaning
Added path searching to rustdoc
When a key is pressed and held, this now does the OS-style repeating after a bit
of a pause. Also fixes the width of search results to be correct (was changed
beforehand and didn't catch this).
Removes old rustdoc, moves rustdoc_ng into its place instead (plus drops the _ng
suffix). Also shreds all reference to rustdoc_ng from the Makefile rules.
