Code Review: V4bugs (take 2)

tfpt review “/shelveset:V4bugs;REDMOND\tomat”
Comment :
DLR:
Marks generated assemblies by SecurityRulesAttributes.

Ruby:
Corrects paths in run_syntax and MSpec (ruby_exe.rb).
Adds RubyIO subclass to avoid type gen.
Fixes tests to run correctly in V4 partial trust

Tomas