EventStream starting position configurable
remove first network check
Merge branch 'master' of github.com:TLuthra/box-java-sdk

Conflicts:
	src/main/java/com/box/sdk/EventStream.java
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.