Fix hard-coded alloc size.
Merge pull request #53 from yallop/32-bit-fixes

Fix hard-coded alloc size.
Split static semantics (types and type formatting) out of ctypes.ml
Split out dynamic semantics (execution, value printing, views).
Remove some unnecessary type ascriptions.
Type printing module.
Value printing module.
Split out and rename Identify_closure module.
Split out stubs used only in the static semantics.
Split out stubs used only in the dynamic semantics.
Split out stubs for standard views.
Improve the type of seal.
Keep basic type details (size, alignment, name) in OCaml, not in C.
Distinguish bufferspec and callspec; move some types out of Ctypes_raw.
Split string/pointer stubs into raw_pointer_stubs.c