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 beyond pull request: https://github.com/D-Programming-Language/dmd/pull/538

Supersedes: https://github.com/D-Programming-Language/dmd/pull/945

Improves issue: http://d.puremagic.com/issues/show_bug.cgi?id=1427
Fixes issue: http://d.puremagic.com/issues/show_bug.cgi?id=5461