Patch child_process.fork to run .coffee files
found a linear shift of lineno, dirty patch for now

It seems that js -> coffee line mapping has a linear shifting.
Dirty patch by applying linear correction.
Dumb, but maybe a hint.
Apply modifications by @jwalton
Improve literate mode.

* Expect a blank line as delimiter between text and code (#2821).
* Don't change indentation of code. It is not necessary and leads to
  erroneous locationData. (#2835)
* Don't modify blank lines and reverse the change in the lexer.
* Don't ignore indentation with mixed whitespace.
Test case for literal mode: Code blocks must be preceded by blank line.
Compiled JavaScript files for improved literal mode.
fix path handling on Windows
Merge pull request #2840 from MattKunze/windows_paths

fix path handling on Windows
Merge pull request #2838 from marchaefner/master

Improve literal mode.
Fixes #2555
Merge pull request #2827 from hden/lineno

Lineno
whitespace
Fixes #2478 -- mention js2coffee in docs
use btoa as base64 encoder, inspired by @ashtuchkin
fixed lineno
safer browser check
better naming by @michaelficarra
Merge pull request #2847 from hden/browser-source-map

Browser source map
small stylistic change and optimisation to code from #2847
be a little more descriptive, as per @epidemian's suggestion