Fixed signedness warning. Why is array size signed?
Remove unused function zap_placeholder.
Fixed #pragma clang warnings.
Fixed autoconf induced PACKAGE_* warnings.
Improved type checking.
AutoDoc: Classes may have submodules...

In some circumstances classes can contain submodules. One example
being Nettle.BlockCipher()->CBC.

The documentation for such submodules was lost in the HTML-generation step.
block_allocator: do not round up powers of 2

The family of round_up* functions rounds up to the next power of two.
This made most block allocators initial areas twice as big as intended.
Fixed some warnings about unused parameters
Whitefish: fixed init_*_struct and exit_*_struct prototypes
Pike cleanup: fix double free

Static strings created with the MAKE_CONST_STRING macros need not be
manually freed. In DO_PIKE_CLEANUP mode they are freed automatically,
or else they are intentionally leaked on program exit.
Gmp: get rid of warning
pike_types: avoid the extra static storage
Nettle.BlockCipher16.CCM8: Fixed documentation reference.