Turn on C++11 features

Technically, maybe this should go into an autoconfig site file..

But I want stuff to build without everyone configuring their site, so..
I guess for now we'll go with this.
Add a getState() method to Process
Add basic ProcessGroup functions to add and wait on processes.
remove test_* from gitignore

Whoops, this was also ignoring src/test_*

And anyway, its better to build out-of-place than add stuff like this
to .gitignore