Added functions for listing the directories being indexed.
Fixed environment handling bug.
Added support for resetting a directory's index contents on rebuild.
Merge branch 'master' into list_dirs

Conflicts:
	codesearch.el
Merge branch 'list_dirs'
Merge branch 'master' into reset_on_rebuild

Conflicts:
	codesearch.el
Merge branch 'reset_on_rebuild'
Removed notion of "reset" from build-index.

It was wrong-headed to have it there.
Renamed clear-index to reset.
Made output clickable.
Updated README.
Switched README to markdown.
Update README.md