Libhxl

- 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

Interim release to decrease log levels and thus reduce the amount of generated logs.

Interim release, mostly around logging changes to support the HXL Proxy.

- 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