Avoid requiring byteswapping functions

Instead of byteswapping a 32 bit word and writing it out as a
whole (which could even possibly lead to crashes due to
incorrect alignment on some platforms), write it out explicitly
in the intended byte order.

This avoids having to set a define indicating the endianness.
Make the deblocking handling endian independent

This avoids having to set a define indicating the endianness.

This doesn't incur any significant measurable slowdown.
Move declarations of functions in expand_picture.asm into a header in common
Move declarations of functions in mc_chroma/luma.asm into a header in common
Use bool_t instead of BOOL_T

One bool typedef is already more than enough, two is too many.
Use bool instead of bool_t

bool is one of the built in, standard types in C++, there's no need
for a typedef for it.
Use void instead of void_t

There's really no reason for adding a typedef for void.
Use char instead of str_t
Use the C++ constants true/false instead of defining our own

TRUE/FALSE has intentionally been left in use for the few
platform specific APIs that define these constants themselves
and expect them to be used, for consistency.
Merge pull request #258 from mstorsjo/endian-cleanup

Avoid endian-specific code
Merge pull request #271 from mstorsjo/merge-asm-headers

Merge declarations of shared asm functions into the comon library
Merge pull request #274 from mstorsjo/typedef-cleanup

Remove typedefs for standard C++ types