category search fix, select function with keyboard

Updates:

- Search on category tab should be working now
- Once you start typing, a function should be selected. <enter> will go to the selected function, <up> and <down> move amongst functions
- added grunt-cli to package.json so don't have to globally install
- reorganized some things

Have a few more ideas but gotta run so figured I'd throw this up here first. Probably introduced some new bugs as well! First time working with these docs :smile: