Hxl-proxy

- bug-fix release: update to libhxl 4.5.1 so to avoid crashes when
parsing a bad date
- use DEBUG config parameter to decide whether to catch exceptions
and display human-readable error messages

- added option to cut-column filter to skip untagged columns
- better error report for a private Google Sheet (or other cloud
file)
- added files from teodorescuserban for building a HXL
Proxy Docker image
- fixed updating source for a saved recipe (short URL)
- support saving data as a JSON list-of-objects (as well as
list-of-lists)
- allow users to specify number format for clean filter

- send JSON error messages instead of HTML when the user is trying to download a
JSON or CSV file
- add subpath support, so that URLs will be correct when the Proxy
is mounted in a subpath in WSGI
- remove H.ID login link for now, since it doesn't do anything,
and is potentially confusing
- require libhxl-python v4.4 for improved exception handling and
JSON support

- require libhxl-python v4.3 for bug fixes
- fixed reference to old HDX URL (leading to SSL error)

- change SSL verification logic to skip verifying SSL
- redirect back to source page if any URL fails SSL cert check
- function changing changes

- add a verify checkbox to the source page; if unchecked, don't
try to verify SSL certs (checked by default)
- add UI support for the new fill-data filter
- added support for new date_format field in clean filter
- support reading new JSON-based input (via libhxl-python)
- use MIME type and extension where avialable to help choose input
type (via libhxl-python)
- use the character encoding specified in the HTTP response when
reading a dataset (via libhxl-python)
- more flexible handing of invalid SSL certs (via libhxl-python)
- new "is (not)" operator for row queries (via libhxl-python)