Added method for retrieving conflicting event ids
Removed unused json import
Added method for retrieving conflicting events
Fixed bug causing exception in conflicting_events() when no conflicting events existed
Added doc for conflicting events
Added tests around conflicting events
Merge branch 'development' into master
Merge branch 'master' of github.com:linkedin/pyexchange
Added un-implemented conflicting_events method to base class
Merge pull request #25 from txstate/master

Support for getting conflicting events