align(n) now fills skipped bytes with '\0'.
align(n,f) to choose a different fill value.
No other changes intended
Use intrinsic byte order swapping builtins for gcc, clang, and msvc.
use assert() to check pre/post conditions.
Remove unused condition macros and unreachable code.
Add tests of byte swapping primitives and
test the correctness of unaligned operations.
add illustrations of flip() and rewind()
