Alter comments
Fix string textobj WRT #"patterns"
Reorder mappings
Add default mappings for wrap_square and wrap_head
Map as <M-S-*> to be more obvious
++todo

Add macro characters for common lisps
Restore g:sexp_enable_insert_mode_mappings

<Plug>s are all available; users can simply map if they wish. This
setting is not granular enough to be useful, and more granularity is too
complicated.
Map to <LocalLeader> per convention

I prefer mapping to my <Leader>, but I suppose that's why these mappings
are configurable.
Register only one command per FileType

We were littering the autocmd table with one autocmd per mapping, per
filetype.