Keep Empty (#13)

Merge pull request variadic mode

merge custom regex date_kv and allowed custom regex for variadic kv

added parsers for kv and json - variadic mode

Merge pull request #11 from rem7/log_line

added optional json format log_line to kv parser

Merge pull request #10 from davsy17/bufferFlush

buffer patch

Merge pull request #9 from davsy17/configTimestamp

configure and format timestamp values going through pushr

Merge pull request #8 from davsy17/safeWinTail

open file for windows

Merge pull request #7 from rem7/open-file

rotate-safe open file flags per os

Merge pull request #6 from rem7/s3_enhancements