Fixed issue where the 'read' method on response objects always return strings

[mraineri]

Fix #125

I looked further at the history of some of the response methods, and this is what I can gather:

• read returns raw contents (as bytes)
• text returns the response as a string
• dict returns the response as a dictionary

When converting to use requests, read was erroneously changed to always return a string. However, one thing worth noting is if someone is using the mechanisms in place to set data in the response object, read will be converted to a string. We should look at this further to ensure consistency, but that might break usage for others. The functionality we have in this PR is equivalent to what we had prior to moving to requests.

[ldonova1992]

Fix has been tested and passes. Everything looks good, thanks!

[jautor]

Approved 5/6