First round of changes for 64-bit port: base

[Mike via Digitalmars-d-dwt]

Please take a moment to review my changes for the `base` 
repository.  It compiles in DMD 2.065 Arch Linux 64-bit with 
either -m32 or -m64.

It's my understanding that the Java classes all use `int` for 
lengths, indexes, etc... so my approach was to simply cast the 
underlying D `long`s to `int`s so the Java API remains the same.

I would like to know if I'm on the right track, so please take a 
moment to give my changes a peer review.

https://github.com/JinShil/base/commits/master

Thanks,
Mike