Add a qwerty homekeys layout option for key selection

Instead of 1234 or abcd, for users of qwerty keyboards it seems
reasonable to use the home row keys for choosing different windows to
switch between. Least distance travelled and all that such. The only
problem is what to do after reaching the somewhat low limit of 8
homekeys - I elected to add a few more (w, e, i, o) that seemed easy
to reach, but it looks like if I were to have too many windows open,
invoking switch-window just fails.

The old options (alphabet and quail) should still work the same as
before, I'm trying to just add a new option.
Whoops, fix errant paren
Implement the qwerty shortcuts using defcustom
Merge pull request #12 from gempesaw/add-qwerty-homekeys-option

Add a qwerty homekeys layout option for key selection
Make the custom variable switch-window-qwerty-shortcuts a 'list.
Update README links, fix #13
Fix README links
Merge pull request #14 from titanofold/master

Fix README Links