Upgrade The ReadMe To Provide Use Examples For Common Resources

This is my first attempt at a formal pull request and first contribution to open source. 

I'm going to try and attach my pull request to this ticket using hub after creating it. 

Please let me know if there is a preferred way of receiving this request.

*File Section*

After we spoke this afternoon I added a section on getting files for a given message_id. However, I use the raw api_attributes call to pull this off. Happy to do it another way if you'd like to point me at the proper method and approach. 

*Querying Dates Section*

I've been able to get expected results back passing in Time.new.utc.to_i but have been unable to get results back passing in Time or Date objects. Is this intended behavior? If not, can I get an example using one of these object types?

Advice, feedback and change requests welcome.