slice allocator

[Philip Kovacs <kovacsp3 comcast net>]

Anyone happen to know at approximately what memory size the slice allocator
defaults back to g_malloc?  Just thinking that if my allocations are too large
for the slice allocator, causing it to drop back to g_malloc anyway, that I 
should consider using g_malloc directly and using GTrashStack to reuse these
memory chunks manually.

The goal of course is to reduce heap fragmentation.