vimrc: Add some new stuff.
shell/aliases: Add urldecode.
irssi: Add a second freenode network.
dwb: Add a new keybinding. Enable page cache.
xmodmap: Add some mappings.
Revert "xmodmap: Add some mappings."

This reverts commit 97e299a1369b8e19c476d645d4b395c4f8ad92cf.

This caused too many problems.