use the built-in AndroidContext to create the Manager object.
removed database proxy cache usage for now -- it causes a "java.lang.IllegalStateException: attempt to re-open an already-closed object: SQLiteDatabase" error
restored database proxy cache and it seems to be working ok.
added tests for query methods
fixed old method name in createDocWithProperties()
004_all_docs_query unit test working on Android
005_database_validation unit tests passing; refactored some of the revision and validation classes.
clean up databases before test
006_document unit tests passing.  Changes include:

* added a document proxy cache to DatabaseProxy
* refactored the revision proxy class structure
* cache the current revision proxy in DocumentProxy
* fixed issues with type conversion in TypePreprocessor
removed rejectWithMessage in favor of overloaded reject()
changed revision.document to revision.getDocument().  This was required to remove a circular reference loop in Android.
all of the 006_document* unit tests are passing now. Changed RevisionProxy.document property to getDocument() method to break a reference cycle that was causing a stack overflow on Android during unit testing. This probably wouldn't have been an issue with normal use, but I didn't want to have the potential for crashes when if the app compared or logged proxy objects.
removed rejectWithMessage; now reject() takes an optional message.
refactored the document unit tests into three different files for clarity.
implement AbstractRevisionProxy.getAttachment() and fix getRevisionHistory()
fixed deleteDocument() so it returns the proper tombstone revision.
added missing proxy properties to UnsavedRevisionProxy
move toRevisionProxyArray() to a static call in the module class.
changed old getDocument() calls to createDocument()
changed call to old document property to getDocument()