Began unittests

Began writing unittests. Written 2 so far looking at the title of a question.
Merge pull request #12 from ChillarAnand/master

added fixtures for user
Removed fixtures

Have removed fixtures from being used in tests, but left the json files there for now as the data will come in useful in other tests.
Merge pull request #13 from sopython/remove_fixtures

Removed fixtures
Removed fixtures and added a constants file
Began Question class

Beginning Question class in nidaba.core.question.Question
Created Question signature

Have got a basic working Question object which can be passed a dict and also a list of Answers.
Added Answer object

Added basic Answer object. Also changed the Question object so that it accepts the answer details as a dict and then creates a list of Answer objects.
Fixed Question object
Moved objects from individual files into an objects file.
Added Comment object
Modified __data to _data
Merge pull request #14 from sopython/question_object

Merging #14
Merge pull request #1 from sopython/master

update fork