Python-fmrest

Added option to pass (HTTP) `timeout` (in seconds) to `Server` instance. This takes precedence over the now legacy `fmrest_timeout` environment variable. When not passed, the behavior is as before (env var, if set, otherwise default 10 seconds from `const`).

When FMS' web server responds with a Bad Gateway error (for example when the Data API is not enabled) fmrest now throws a custom exception to be able to easier catch this situation.

Additionally, when using the context manager, the `__exit__` will from now on only perform a logout when a token exists (as a logout would always fail when no token is available).

What's Changed

* Fix: Empty display values now default to an empty string in `get_value_list_values`, submitted by LeJeko in https://github.com/davidhamann/python-fmrest/pull/64

**Full Changelog**: https://github.com/davidhamann/python-fmrest/compare/v1.7.0...v1.7.1

What's Changed
* Full layout metadata now available via `get_layout()` (see `metadata` parameter), ability to retrieve value list values via `get_value_list_values()`, ability to control response date format by providing a `date_format` keyword to `get_record()`, `get_records()` and `find()`. Submitted by LeJeko in https://github.com/davidhamann/python-fmrest/pull/63

The `Server`'s methods can now take a `request_layout` argument, where applicable. This layout take precedence over the current `Server.layout` attribute and is helpful if you want to have a shared `Server` instance in a multi-threaded app and make sure to have the right layout set before making a request.

Example (using `my_custom_layout` to get records, even though `my_default_layout` is set on the `Server` instance):


>>> print(fms.layout)
my_default_layout
>>> fms.get_records(request_layout='my_custom_layout')


Some methods already had a `layout` parameter. This parameter is still there and works as before but now throws a deprecation warning. Please use `response_layout` instead of `layout` from now on. It has the same effect and is easier to distinguish and more clear to understand.

* Configure proxies for auth requests made to Cognito
* Configure proxies for FileMaker Cloud Data API

Note: when configuring a proxy and you're not just using it for local debugging (e.g. a local interception proxy), always make sure you trust the proxy server and use a secure connection.

Thanks TDKorn for the PR!