More ITS#6215 -

More ITS#6215 -
Speedup & less memory allocation:
  Simplify the work to encode tag, length, integer/enum, sequence/set.
  Drop struct seqorset and allocations of it.  Replace BerElement.ber_sos.
  Drop ber_write(,,,nonzero) support. Callers, if any, need to be rewritten.
  Make ber_log_sos_dump() and ber_sos_dump() stubs, they could no longer work.
Fix ber_write() buffer overrun after ber_start_seqorset().
Check overflow and max sizes, e.g. for functions returning int size.
Some cleanup, and handwaves in the direction of supporting CHAR_BIT>8.
Add/fix comments and a few descriptive types/macros.