DI Generation Improvements.

[LightBender]

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: #538

Supersedes: #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

[denis-sh]

As @klickverbot noted in #945 discussion, now we have another meaning of -inline and have no ability to generate optimized code (i.e. -O -inline) and strip function bodies from headers in single dmd call. It is not a big problem but as some people think that it is a redundant things complication and have no sence it should be properly documented.