Facebook import and extended contact parameters

Features/Changes Made: 

- Added Facebook Contacts Import. 
- Retrieved additional parameters from contacts from all the networks (facebook, gmail, yahoo, hotmail): 
  It now fetches: 
	1. name
	2. first name
	3. last name
	4. email 
	5. gender
	5. birthday 
	6. relation
	7. id
	8. profile image (only for facebook and hotmail for now)

- Fetch gmail response in json format instead of xml. This is to make it consistent with response formats from other networks. 
- Updated https_get headers default parameter to make it compatible with Ruby 2.0
- Raise_error matcher updated to latest Rspec specifications. 
- All importer specs updated to test the latest code.