fixing fork count bug in the runner
fixes to workflow/activity output/exception size bugs
fix for workflow_client not using user supplied data converter
refactoring truncation logic into a utility
fixed truncation logic and wrote more unit and integ tests to confirm large workflow/activity responses/exceptions are being handled correctly
Fixing a bug that was preventing CancellationExceptions initialized without a reason to go through
some more fixes to workflow/activity input/output limits
adding validation check for cancellation exceptions as well
moving error string into a separate utility function
Bumping version to 2.1.0
Merge pull request #71 from pmohan6/master

Bumping version to 2.1.0 and multiple bug fixes.