New node type `propertyDelim`
Tests: Catch errors (show which test failed)
Sass: Support indented syntax

- Blocks without `{` and `}`
- Declaration delimiter is `\n` instead of `;`
- Property can start with a semicolon: `:color tomato`
- Mixin `=nani` or `= nani` (same as `@mixin nani`)
- Includes: `+nani` but not `+ nani` (same as `@include nani`)
Rename node: decldelim -> declDelim
Clean up

- Reorganize code
- Move mark functions to syntax methods
Make parsing of comments syntax specific
Sass: Support indented comments
Tests: Minor clean up
Update docs
Sass: Fix placeholders + add tests
New node type `escapedString`

`~'ms:nani'` -> `['escapedString', ''ms:nani'']`
Valid only for less.
Css: Check spaces and comments outside progid
Update changelog