fixed compile error in millie

millie/move.c was failing to build with the following error:

move.c:336:15: error: comparison of constant -1 with expression of type
'bool' is always false
[-Werror,-Wtautological-constant-out-of-range-compare]
        Next = (Next == -1 ? FALSE : TRUE);
                ~~~~ ^  ~~
1 error generated.
*** Error code 1

I added stdbool.h to the mille.h header, changed the case of the
true/falses in the file and replaced the -1 and checks with a less
ambiguous version.

The actual (ie non-case changes) are on line 325, 330, and 336 and are the removal of the -1
assignment and the ternary to convert the -1 back into a boolean.  

This was done on 

Darwin bebop.local 12.4.0 Darwin Kernel Version 12.4.0: Wed May  1 17:57:12 PDT 2013; root:xnu-2050.24.15~1/RELEASE_X86_64 x86_64

with cc (clang):

Apple LLVM version 5.0 (clang-500.1.74) (based on LLVM 3.3svn)
Target: x86_64-apple-darwin12.4.0
Thread model: posix