Added installation of phantomjs through the phantomjs package. closes #13

- updated dependencies and updated the wrapper
- updated the readme because the dependency is now handled automatically
  (so the user doesn't need to worry about it)
Changed create-page script to use websockets for communication with phantom

- phantomjs process is now spawned and kept alive until all the pages
  have been created
- instead of writing and reading files, we're passing page contents and
  overflow via websockets same way as node-phantom
- for that purpose we've got a bridge script that wraps around the
  create-page script and takes care of the websockets
refactoring bridge and wrapper to make it easier to add more phantom scripts
applied websockets to create-pdf-page script
lint
Tweaks & improvements

- changed the phantom scripts to use the built in module system
- added better handling of events listeners
- added note about using the node-phantom method of communicating wtih
  phantomjs
working on initialisation

- phantom-wrapper methods now self-initialise if they need to
- added extra cleanup method for the phantomWrapper in main.js
cleaned up unused pathsToPdfs array
changed the way phantom process is killed

that was needed because only node child processes can be disconnected (I
think?)
fixed issue with images not being loaded properly

The proper phantomjs handler needed to be used to guarantee that all the
images have loaded before calling the callback
Merge branch 'feature-phantom-refactor', closes #7
bump to 0.3.5