Add support for ignoring files

Ignoring files is now possible by specifying a list of patterns
in opts.ignore
Fix issues with --standalone

When browserify is invoked with --standalone, the bundle() will return
a through2 stream. This stream does not emit the 'close' event. The 'end'
event comes through though.

Switching watchify to use the 'end' event seems to work with and without
--standalone option.
0.6.4
Merge branch 'feature/ignore-node-modules'

* feature/ignore-node-modules:
  Add support for ignoring files