Add pure logging for HTTP/S requests

[operatorequals]

This is quite self explanatory.
It is quite useful to have a log of all the requests made by this module, maybe by a different logger than the httpimport one:

req_logger = logging.getLogger("httpimport.requests")

so it can have all kinds of controls like, log to file, colors, etc.

When debugging, or when working with network issues this could be a useful tool.

[john681611]

So far the lack of feedback or throwing of an error when a network call is rejected is far from ideal