Cherry pick from cliffc-auto branch

Not GIT cherry-pick, because we need to tease apart lots of files.
Fix race bug in VA->FV converter not blocking on chunks being created.
Fix also in TestUtil va_maker.  Fix also in Frame deepSlice.
Polite PCA msg when only 1 column.
Fix 32/64 bit overflow in UploadFileVec
SetColumnNames handles a list of string headers; source Frame renamed to
copy_from
Cleanup UKV.remove logic.
Cleanup FV->VA wrapper logic.
Turn down RollupStat logging.
Missing null chk in RequestBuilders, ParseDataset
Remove a windows-fail from Makefile
Use named constant instead of 1+1+4+4
Remove dead Key types; some dead functions; fix some bad spacing.
Merge branch 'master' of github.com:0xdata/h2o
Cherry pick from cliffc-auto