Add nodatetime.ddoc and hook position

Stop insertion of generating date and time into html file.
This is useful to check ddoc feature regression.

Command Line:
    make -f win32.mak NODATETIME=nodatetime.ddoc ...
Merge pull request #310 from AndrejMitrovic/DocumentMain

Document -main switch.
Merge pull request #308 from 9rnsr/no_datetime

Add nodatetime.ddoc and hook position
Supplemental changes for Fix3673.