Fix for issue #8 - handling paths in windows.
Update node-webkit download url
Update to latest version of node-webkit
Only add .exe extension for default app and bin names when using windows.
Add command line options to docs.
Merge in changes from https://github.com/JustinJudd/golang-nw/commit/3c3235ff8a45ded31b65cbee456c2010069ef8ed.
Update known issues