Adopt some syntax highlight features from Clojure Sublimed

[imrekoszo]

In a recent Clojure Visual Tools meetup Nikita demoed Clojure Sublimed. I found some color scheme/syntax highlight features intriguing and would like to see these in Cursive.

I haven't done extensive checking of which of these might actually be available and I just don't know about them.

1. Quoting and unquoting background to help identify where these sections begin and end:

2. Faded _unused symbols, namespaces in qualified symbols:

3. Ability to style metadata and rich comment blocks special:

4. Different comment styling based on the type of comment used, faded whitespace-commas:

5. Error detection:

Related parts of the demo:

1. 18:11-26:24
2. 34:38-39:06