Fix syntax error
ast::Purity renamed to ast::FnStyle
str is no longer mut, so use StrBuf instead when needed
Use a leading underscore to suppress warnings for Profiler RAII
Check for an return errors in write_call_graph() instead of printing
remove unused usees
Merge pull request #28 from radford/fix-updates-cleanups

ok i'll merge it on github and take your word for it that it compiles. 'callgraph.rs' will get some changes back soon.