Cleanup + support append to topic and individual pasties.

Moved config.json to config.json.template
Moved port number to separate config field.
Updated app server and cli script to get port from config.
Fixed per-user pastie tracking in server code.
Added support for topic threads.
Updated cli script to support appending to topic and printing
individual pasties and topic threads.
Remove whitespace.
Sensibly include the .html suffix.
sending all data as base64 encoded to allow sending of binary data
adding support for png pasties
Merge branch 'master' of https://github.com/travisj/pastie
Merge branch 'travisj-master'
Merge from jhuttner remote.