-> New memory allocator for Bmesh

Added a new pooling allocator for Bmesh based upon
the pool allocator availible in the Boost C++ library
as described here:

http://www.boost.org/doc/libs/1_34_0/libs/pool/doc/concepts.html

Each pool allocates elements of a fixed size, so every
element type in a mesh gets its own pool. For instance
verts occupy a different pool than edges. Each pool
is comprised of multiple arrays of a fixed size and allocating
/freeing elements is simple as removing or adding a head 
to a linked list. Since the list of free elements is interleaved
throughout the unused space in the arrays, the overhead
for storing the free list is only 1 pointer total per pool.
	
This makes building/destroying bmesh structures much faster
and saves quite a bit of memory as well.

source/blender/src/editmesh_tools.c

@@ -4497,7 +4497,7 @@ void bevel_menu() {
 	while(G.editBMesh->options & BME_BEVEL_RUNNING) {
 		options = G.editBMesh->options;
 		res = G.editBMesh->res;
-		bm = BME_make_mesh();
+		bm = BME_make_mesh(512,512,2048,512);
 		bm = BME_editmesh_to_bmesh(G.editMesh, bm);
 		BIF_undo_push("Pre-Bevel");
 		free_editMesh(G.editMesh);