Bikeshedding fun: suggest a name for 64 bit Phobos library

[klickverbot]

Please, please just call it libphobos2.a on Linux and move it to the 
64bit library directory. On OS X, one might want to build it as 
universal binary, so no special casing needed there either. On Windows 
it is installed to the DMD directory anyway, so this is probably no 
issue either (3d-bit-dmd/lib = 32 bit Phobos, 64-bit-dmd/lib = 64 bit 
Phobos), but I am no Windows guy.