Fix parsing of error response

Prior to this commit, only json response containing a meta attribute
were parsed properly. Instagram can also send a response body that
is the content of the meta attribute itself.

This commit adds a method that parses both cases properly and
updated the tests to take that into account

Fixes gh-58
Merge pull request #60 from snicoll/gh-58

Fix parsing of error response
[maven-release-plugin] prepare release jInstagram-1.0.7
[maven-release-plugin] prepare for next development iteration
Updated artifact version number.