Remove now-unneeded workaround for bug# 4866.
Fix functions which are supposed to return by ref in SysTime.

Compiler bugs previously prevented these functions from returning by
ref.
Fix functions which are supposed to return by ref in Date.

Compiler bugs previously prevented these functions from returning by
ref.
Merge pull request #2222 from jmdavis/datetime

Remove workarounds for some compiler bugs which were fixed