Closes #4448

Issue #4426

Closes #4437

Closes #4432

Add template/variable definitions, checking, types, additional
keywords and indentation fixes.

Closes #4401

As per CommonMark (conflicting with markdown.pl, but never
mind markdown.pl)

Closes #4395

As described in http://caniuse.com/#feat=user-select-none and https://developer.mozilla.org/en-US/docs/Web/CSS/user-select

Issue #4374

 - Added for as a defining keyword
 - Added new types and operators
 - Fixed numbers so basic integers are represented
 - Identifiers can now be surrounded with backticks
 - Properties and #/@ instructions are now distinct, with the latter represented as a builtin type
 - Properties are now matched before punctuation. Code can now fold.
 - Remove the regexp checking as that syntax does not currently exist in Swift
 - Added tests

and adds the xù specific keyword 'xu'

Closes #4345

Demo had the correct `text/x-vue`
defineMIME was using `script/x-vue`

There is, however, no `script/*` top-level media type:
http://www.iana.org/assignments/media-types/media-types.xhtml

Left, old `script/x-vue` for backwards compatibility.

Closes #4340

Closes #4325

Closes #4325

And fix another bug introduced by 329b9e6e

Closes #4310

* commands are first in a line
* constants can contains more than `\w`, e.g. `${xml::CreateNode}`
* same goes for language strings

Closes #4297

Closes #4256