DI Generation Improvements.

This pull request improves the follow DI generation rules:

All functions stripped of their implementations except for template functions and auto return functions.
Improved indenting.

Requires: https://github.com/D-Programming-Language/druntime/pull/218
Supersedes: https://github.com/D-Programming-Language/dmd/pull/538

Fix issue: http://d.puremagic.com/issues/show_bug.cgi?id=1427
Fix issue: http://d.puremagic.com/issues/show_bug.cgi?id=5461