Update demo app for Xcode 5, iOS 7
Merge branch 'master' into development
Update unit tests project for Xcode 5
Fix compiler warning
Add abstract in document update properties
Add `fixedTimestamp` property to `MDLMendeleyAPIClient`

This property has become necessary because the server often rejects iOS devices system timestamps.
Fix crash when trying to create document with nil title
Add journal article document type constant
Bump to version 1.3.2
Merge pull request #13 from shazino/development

MendeleySDK v1.3.2
Migrate to AFOAuth2Client for new OAuth 2.0 authentication process
Remove .gitmodules file
Update readme about OAuth 2.0 migration
Clean code
Update copyright notice
Clean gitmodules
Clean code
Update MDLMendeleyAPIClient with `configureSharedClientWithClientID:secret:redirectURI:`
Update readme for OAuth 2.0
Update readme regarding client credentials flow