Remove all Implementation from Header files

[katyhuff]

Robert brought up the fact that this would greatly speed up build time during subsequent builds. It'll add more to the implementation file, but the implementation file will directly match the header file.

[katyhuff]

This issue came from https://github.com/cyclus/core/issues/111 . Go there for previous comments.

It was originally opened by @gidden .

[scopatz]

Has this been completed in our recent refactorizations?

[gidden]

Not precisely, but I don't think this is a specific enough issue to keep open. I'll reopen something if it comes up.