Update .travis.yml

Reformat for readability.
Update setup.sh

Remove DataMapper dependency installation and update rake task
execution.
Rename q_title to q_name to be consistent with Moodle

Change the name of question name and add in simple validation for
question types.
Add categories to the model and associations with questions

Categories and questions have a has_and_belongs_to_many association. A
default user account is added to the seed - all new questions default to
being owned by this user if not specified. database.yml development
group set back to mysql2. Answers model and migration on standby,
pending appropriate modelling for different question types.
Change question type names to Ruby naming convention

Use underscore-seperated words instead of camelCase.
Update answers model and related models

Use the Moodle question_answers table as a base for the answers table.
Added comments to category and question models.