Fixes a stack overflow

The actual stack overflow observed occurred in debug mode, with a test file
that consists of a repeated pattern.

The binary tree dtor used in verificationhashtable.h recursively deletes nodes.
Each node deletes its left and right child (fine) and the next node with same
crc & hash.
But the `same` nodes are not stored in a tree (with log(n) depth) but in a
linked list. Therefore, deleting them recursively can lead to a stack overflow
(if there are many of them).

The fix replaces the recurrence of deletion of `same` nodes by a loop.
Left and right child nodes are still deleted using recurrence.

This is rather a quick-and-dirty fix, as I don't really know how the tree
itself is used from the outside (what's the owner concept? not clear).
Adds VS2010 solution and project files and pthreads property sheet

The property sheet allows quick adjustment of the pthreads path.