More cleanup of Errors -- including sources as a factory method rather than push/pop methods (that require try/finally clauses)

I'll want to get this for InjectionPoints sooner or later also.

Also merging AddMessageCommand and AddThrowableErrorCommand, with a command that ads an spi.Message.

git-svn-id: https://google-guice.googlecode.com/svn/trunk@532 d779f126-a31b-0410-b53b-1d3aecad763e
25 files changed