+ Enables web-mode's autopairing functionality
+ Prevents duplicate >'s after web-mode autopairing.
+ Leave longer-than-3-character pairs to smartparens (there was only
<!-- -->)
+ Remove <?p -> <?php | ?> autopairer. Leave that to snippets (web-mode
doesn't support prefixes longer than 3 letters, and <?php ?> is too
much of a performance drain to have smartparens support it, so I added
a "php" snippet that expands to <?php | ?>).
+ Tags now auto-close when you finish typing the opening
tag. (web-mode-auto-close-style = 2)