srl_buffer.h: improvments to varint and zigzag processing
bench.pl: more ways to benchmark, and tweaks
srl_compress.h: Better compress_flags handling

And fix a type mismatch bug. enc->flags is U32 not U8
hobodecoder.pl: load constants better
hobodecoder.pl: cleanups and fixes
TestSet.pm: change the test set so it does not include multiple ints in a row

So it tests what it is supposed to test once we introduce MANY.