Removed possible testing and unreachable code to avoid JavaScript
compiler errors:

...
codemirror/mode/coffeescript/coffeescript.js:271: WARNING - unreachable code
    if (false && current === ".") {
...

Node's 'mime' package gives me text/coffeescript for this.

And remove some unused state properties

That's what the parser configuration object is for. Also,
I am unsure how this was supposed to even work.

Issue #2996

- Using `@` as `this`
- `and=` and `&&=`
- `or=` and `||=`
- `?=`

Closes #2817

Issue #2807
Issue #2814

Bumping them for every release just adds too much git
noise and history blowup.

Closes #2050

Issue #1932

Issue #1932

Issue #1882

Closes #1779

Moving to a situation where there's only one LICENSE for the whole
distribution.

IE<9 does some truly messed-up things when it sees these.

Another great JS feature banished for the foreseeable future by
the bunglers in Redmont, sigh.

As spotted by the extended linter.

f = @ and f = fun(@) would not highlight properly
  i changed @property to highlight seperatly as @ property
  which i think makes more sense because its a shorthand for
  this.property and this and property have different colors

$ is a valid identifire
/path no longer breaks
0...1 no does not highlight as 0. .. 1
removed some spaces on blank lines

Since v2 is the canonical CodeMirror at this point

So that I can put other doc-related stuff there without polluting the
root dir.

It's tiny anyway, no need to force people to include yet another file.