Merge pull request #144 from hardillb/master

Fix random wait in delay node
inject node -  Remove couple of lines of excess console.log
Tweak Inject Fire at Once options as per Issue #145
Clear inject once flag properly. Issue #145
Inject - cleanup messing with crontab... just don't do it.
Slight UI tweak to Inject node - move fire once below options
File node: allow filename to be overridden
Move to twitter-ng module
Fixes #136

This will require an `npm update` to keep things working
HTTP Request: allow message to override https
Fixes #147
Add CONTRIBUTING.md
Update README.md
Improve node info properties table
Fix for bad MIME Content-Type (per #152)
Merge pull request #153 from andypiper/mime-fix

Fix for bad MIME Content-Type
Add rawBody middleware
Fixes #151
Fix drag'n'drop of flows on FF
HTTP In GET error handler fix
Separate out httpAdmin and httpNode
Add username/password to Mongo nodes
Fixes #159
Fix overriding method in HTTP Req node