Merge pull request #3 from Kapeli/master

Make headers conform to package.el requirements
add tuples for some major modes
update version number to 0.0.4
Ignore .elc file
Formatting fixes from checkdoc
Convert dash-at-point-mode-alist to a customizable var
Search immediately, and use C-u prefix to edit search first
Provide a mechanism for setting the docset prefix directly

This allows users to add logic for setting docsets based on
minor modes or other information, e.g. sql-mode connection type.
Mark code in README as lisp