Libhxl

- loosen versions for dependencies
- remove dependency on requests_cache

- milestone release
- fix URL munging for direct-download HXL Proxy URLs
- add hxlinfo command-line script
- added headers and hxl_headers fields to output of hxl.input.info()

- remove hxl.input.ExcelInput.info() and make a top-level hxl.input.info() function that works with every data type (also alias to hxl.info())
- update Makefile for new git branch structure (just dev and prod)

- update requirements to allow latest versions of dependencies
- don't fall back to CSV if we have a MIME type or file extension that's not in the allow list (which is fairly liberal)
- change behaviour of ReplaceDataFilter so that with a map, it stops after the first successful replacement for each value
- change to ReplaceDataFilter means that replacement maps can now have default values at the end
- speed up ReplaceDataFilter by precompiling matching column indices for each pattern/replacement
- simplify Excel handling to remove dependency on mmap and tmpfile
- add patch from wynnw to fix crash reading some local files
- fixed issue where libhxl can't read directly from sys.stdin

- decreasing log level to reduce the amount of logs generated by the HXL Proxy (in prod)

- use structlog module
- add hxl.util.logup function to include function name in log message
- switch to logup in input module
- add extra help text for hxlcount script