Remove fallback alternatives for compiler before GCC 4.7

We (provisionally) settled on a minimum compiler requirement of GCC 4.7. That means we can now be sure that the following features are always present (please complete the list, I probably forgot something):

• template aliases
• constexpr
• auto variables
• range-based for

We should remove the fall-back code paths for those features.

Milestone changed to 2.4

Reassigned to @joe

Assignee removed

I took care of the fallback code for template aliases.

Most people did some cleanup to the C++ style of the local operators while applying API changes. This is probably as much as we can hope for, so I'll close the issue for 2.4.

Status changed to closed