Added new UID datatype

Generates random UID if field exists and is empty or null
Added new demo scripts

Test UID datatype
Changed "datastoreType" to "backend"

The CRUD ControllerConfiguration is looking for “backend” instead of
“datastoreType”
Merge branch 'master' of https://github.com/skavanagh/lightblue into uuid
Fix UIDType to behave like string
Add interceptor
Demo fixes
Update README.md
Scripts no longer spew out data
Updated simple.dot formatting and added 'puzzle' picture in docs
Added docs/overview.png
Update README.md
Use silent curl
Fix #45: indexes on background
Add deme readme
Add db cleanup info to readme
Hook up interceptors
Add UIDFields
Added new UID datatype

Generates random UID if field exists and is empty or null
Added new demo scripts

Test UID datatype