Make all the fields in the various structures just arrays of bytes, so

Make all the fields in the various structures just arrays of bytes, so
we can cast not-necessarily-aligned pointers to pointers to those
structures without risk of compiler warnings *or* the underlying problem
the compiler's trying to warn us about (no, you can't always dereference
an unaligned pointer - SPARC traps, and at least some ARM processors may
do something other than what you want, for example).

This also caught some cases where we were not even properly
byte-swapping on big-endian platforms.

This also lets us not muck around with splitting 64-bit times into two
32-bit fields - we have pletohll(), after all.

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@36787 f5534014-38df-0310-8fa8-9805f1628bb7