Detect ASDF *.asd files as Lisp files.

Manually set `.m` and `.mm` files to Objective C. By default these were
set to `matlab`.

Highlight Hasp files as CSS.

Recent Vims have a built-in JSON syntax plugin which is a little easier
to read than the JavaScript highlighting. Use the built-in one on Vim 8
and higher.

Copy one of the Git file detectors from
`/usr/local/share/vim/vim74/filetype.vim`. This gives me `gitcommit`
filetype features for merge and tag messages even when using a Vim older
than 7.4 (Vim 7.3, the default on many Macs, only sets COMMIT_EDITMSG to
the `gitcommit` filetype).

Additionally, set `gitcommit` on `PULLREQ_EDITMSG` files. This gives me
the same features for pull request messages using GitHub's `hub` command
line tool (in particular spell checking).

Trying out Typescript in a project. Instead of getting a Typescript Vim
plugin, just use the Javascript syntax highlighter for simplicity.

Working on a Rails project that uses Slim templates. Looks like we have
HAML syntax highlighting built-in, so just use that to highlight Slim
files.

Blech, CoffeeScript! Having to read & write some recently, so add
support for it.

Load *.jbuilder files as Ruby so that they can be edited like Ruby files
and have Ruby syntax colours.

I want the HTML matchit command to be available in *.html.erb files.
Normally, these files get loaded as `filetype=eruby`.

The trouble with that is that not all eruby is HTML, so I can't load the
matcher in the 'eruby' filetype because it might not make sense.

Create a new special filetype for *.html.erb files that uses the normal
eruby syntax, but includes the HTML matchit command.