v0.3.6-kpv3

Merge branch 'respect_api_limits'

Kapernikov patch2 to v.0.3.6

Prepare RawExactApi._rest_query() and rename to rest_raw() so it is possible to create mixins for RawExactApi that give access to the HTTP Response headers.
This can (and will) be used for mixins that interpret the X-RateLimit headers to avoid exceeding these limits.

v0.3.6 from ossobv

Debug logs to track outgoing HTTP requests

Adds some debug logs in order to make it easier for consuming libraries
to check which outgoing HTTP requests are being made.