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.
gsoc2013 files
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 branch 'master' of github.com:D-Programming-Language/d-programming-language.org
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