Update default-bindings.el

make comments agree with bindings ;)
update paredit navigation bindings and add new bindings for org mode
update dependencies
Merge pull request #103 from sduckett/patch-1

Update default-bindings.el
Update undo-tree submodule to point to emacsmirror as some users reported issues fetching from www.dr-qubit.org directly. Fixes #92.
Remove pretty symbols λ, ƒ and ∈