Fix return value for isDuplicate in EventStream
Add unit test for duplicate events
Merge branch 'fix-duplicate-event'

Fixes #35.
EventStream starting position configurable
Merge pull request #34 from TLuthra/master

EventStream starting position configurable

Fixes #33.
Remove unused parseSourceInfo method in BoxEvent
Document when BoxAPIException can be thrown

Added additional information in the javadocs for classes that throw this
method. Also added a section on error handling in the overview guide.

Closes #27.
Tweak error handling documentation

* Move the BoxAPIConnection constructor out of the try-catch in the
  example.
* Add a small explanation of what an unchecked exception is.
Add COLLAB_REMOVE_COLLABORATOR event type

This event type isn't documented in the API docs yet, but it is
supported.