Merge pull request #6 from distantcam/fixes

Properties with only getter or setter fix
Verified issue #5 causes no harm. Added async support.
Merge pull request #7 from distantcam/master

Iterator and Async support
try exclude async from build
more edge cases. more tests
add unsafe
fix build
exclude "2"
Fixed some of the LargeAssemblyTests.
Fixed issue with multiple outs not having correct IL.
Fixed issue with nullguards on generic T out parameters.
Added VB iterator support.
Fixed issue where multiple return guards would have incorrect branching addresses.