Mapping for escape key breaks special key functionality in terminal Vim
Configurable syntax highlighting pattern (Ingo Karkat)
Add additional mappings and aliases.

Alias <S-CR> for o and <Esc> for q.
Add <C-CR> to open a file as the :only on.e
Issue error when attempting <C-CR> (open :only) on multi-line selection.
Re-enable <Esc> mapping disabled in upstream.

Though this affects some terminal Vim key bindings, the only noticeable effect I see is the delay waiting for additional keys. Therefore (and because I mostly use GVIM), undo dcdda97fdda7b18c950bca3871c5fb3a1df2d894.