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 ...
added gsoc2013
Use  instead of hardcoded version in download.dd
Remove spaces.
Document -main switch.
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.
Merge pull request #180 from AndrejMitrovic/Fix3673

Supplemental changes for Fix3673.
fix Issue 6024 - Windows 2000 SP4 is not supported any more? And what is still supported?
Merge pull request #312 from WalterBright/fix6024

fix Issue 6024 - Windows 2000 SP4 is not supported any more? And what is...
Fix padded link target "class.html#        nested" in struct.html
Merge pull request #291 from ntrel/fix-padded-link

Fix padded link target "class.html#        nested" in struct.html
fix Issue 8130 - Memory corruption because without *.def file DMD compiles DLL with assumption
Merge pull request #313 from WalterBright/fix8130

fix Issue 8130 - Memory corruption because without *.def file DMD compil...
improve dmd compiler page
Merge pull request #314 from WalterBright/improvedoc

improve dmd compiler page
fix git clones to not require ssh keys

also, gsoc2013 content is missing
Update dconf info.

The conference is over, this should be updated to reflect that.
Merge pull request #319 from John-Colvin/patch-3

Update dconf info.