Heregex bug (fixed in Coffee and Coco long ago)

[summivox]

In Coffee:

///
a\ b\
///

compiles to:

/a b\n/;

But in LiveScript:

1. escaped EOL won't compile
2. space is not properly escaped

I'm looking into backporting satyr/coco@45d3ea3

See:
jashkenas/coffeescript#3059 (turned out I raised this too)
jashkenas/coffeescript#3214