free() doesn't have a size arg.

Requires minor fixups.  "depends" now prefixes ccan/ (allows for 
non-ccan deps later).

Fixed up ccan_tools dir, not other package's tests.

get_page_state.
Combine alloc_get_pages and alloc_from_bitmap.
Fix error in alloc_init (valgrind found uninitialized mem)

found one bug.