[PATCH] Add support for auto-generating LIT tests by the build

[Vane, Edwin]

Note that in libc++ classes are defined not in the 'std' namespace directly:

```namespace std {
namespace __1 {
template<...skipped...>
class vector { ...skipped... };
} // __1
using __1::vector;
} // std```

[REV] Will check to see if the matchers work on this case.

Standard containers have more template arguments, but they have default values.  I did not have time to review the refactoring code yet, so this is JFYI -- your code might be handling those correctly already.

[REV] Shouldn't be a problem for the matchers. They ignore template arguments.


http://llvm-reviews.chandlerc.com/D423