add PROJECT=druntime ddoc macro

- This will be used to customize links in dlang.org's std.ddoc.
Merge pull request #707 from MartinNowak/projectDDOC

add PROJECT=druntime ddoc macro
add project.ddoc to MANIFEST
Merge pull request #708 from WalterBright/add-project

add project.ddoc to MANIFEST
Don't do unaligned accesses
Merge pull request #709 from jpf91/arm-1

Don't do unaligned accesses