Adding support for single-quoted heredocs

[djpadz]

Requirements

• Filling out the template is required. Any pull request that does not include enough information to be reviewed in a timely manner may be closed at the maintainers' discretion.
• All new code requires tests to ensure against regressions

Description of the Change

Adding support for single-quoted heredocs. This commit contains support for the "simple" case:

a = <<'EOF'
This is \'quoted\' \\ properly.
EOF

Alternate Designs

None. This is my first venture into CoffeeScript.

Benefits

Single-quoted heredocs will be supported.

Possible Drawbacks

I can't come up with a way to do this for heredocs that have multiple inputs. Also, if I were to implement this for all of the "embedded" patterns, it would really bloat ruby.cson. I'm open to suggestions.

Applicable Issues

[djpadz]

Just realized that this was already covered in #212. Closing.