Fixed NullReference bug
TryRead threw NullReferenceException when called with null values. Should throw argument null exception.
Merge branch 'rohu/fixtryreadwithnull'
Fixed null argument checks on all context extension methods
Merge branch 'rohu/fixnullcheckonpromote'
Unit tests
Added unit test project
Added basic setup for creating a new test message with a promoted property
Normal case unit test for TryRead helper method
Added test case for trying to read a non existing context property
Test case for calling try read with null values
Promote test case for normal execution
Promote test case for null arguments
Merge branch 'rohu/unittests'