Merge pull request #369 from jonpither/fixing-rotate-display

Fixing rotate and display when current buffer is nrepl buffer
Mention extensions in the README
Clarify Leiningen 2.x requirement
Retrieve the eldoc string synchronously
Merge pull request #373 from herberteuler/synced-eldoc

Retrieve the eldoc string synchronously
Update manual installation instructions
Adding insert-fn functionality