Add projectile, add ido auto-complete support, add lambda pretty replacer

[zacyang]

Hi ,
I read you blog and found this starter tool kit, it's nice and handy.
But still something is broken , e.g auto-complete, so basically I update some of you config. Including:

1. Add IDO hook for projectile
2. Add auto-complete with build-in doc
3. Add lambda symbol replacer
4. Bind c-` as send form to repl to eval and return to current buffer.

[flyingmachine]

Thanks for this PR! I haven't had time to look at it but wanted to let you know that I really appreciate it.