Bringing the hazelcast async executor up to speed with the latest changes in the DefaultAsyncExecutor (in fact, extending from it now)

Added bridge resolver for mock objects to unit test BPMN scripts

businessRuleTask support of activiti:class attribute

Activity cancelled event for process delete API call

fixing missing node drawing in activiti diagram for ThrowEvent and

EndEvent

Fixed an issue with the category attribute being duplicated.  ACT-2067

PROCESS_CANCELLED event implementation

Diagramgenerator draws Message Start / Intermediate / Boundaryevents

Diagram viewer supports display flow name.

`BaseElement.getAttributeValue(String, String)` will throw NullException when the first argument `namespace` is null

when the first argument 'namespace' of BaseElement.getAttributeValue(String, String) is null, it should return the value of the first ExtensionAttribute whose 'namespace' field is also null

correcting some spelling and grammar mistakes.  Other changes include standardizing
on a single form of a word. Examples include i.e., BPMN, LDAP, JUnit, JSON, and JavaScript.
I either selected the common industry usage or the most prevalent usage in the
document.  Thus 'i.e.' was selected over 'ie.'.  In other cases where the usage was
large and split almost evenly I left them alone.  Such an example is 'eg.' vs. 'e.g.'.

minor typos