Replace `f` alias with Clipper helper for use with Mosh

As described in these docs[1], I'm going to try using Mosh for sandbox
connections for a while. This means still using SSH for maintaining a
Clipper tunnel.

So, re-purpose the `f` alias (mnemonic: "forward") seeing as I am not
using Flow anymore.

[1]: https://github.com/wincent/clipper/commit/2741cbc177e483dc50e525c

Signed-off-by: Wincent Colaiuta <win@wincent.com>
Vim: avoid unwanted prompt in <leader>r mapping

We were getting prompted (I don't have the exact text now, but it was
something like "press ENTER or SPACE to continue" each time we ran this
mapping, which isn't very fun.

Signed-off-by: Wincent Colaiuta <win@wincent.com>