DMD 1.039 slowness...

[Bill Baxter]

DMD 1.038/1.039 slowness is still there in DMD 1.040.

A 1 minute build with 1.037 turns into
a >12 minute build with 1.040 (not sure how long exactly, I got bored
waiting to send this email)

Also this change:
* Separated bin and lib directories into windows, linux, and osx.

while probably for the better, is likely to break a lot of installers
and install instructions that people have written for DMD.

It broke the post-install scripts I always run after installing a new
DMD, and means I will need to update the path to DMD in various
places.

--bb