First draft of the introduction

Rewrote the introduction as a usecase.

Pulled the introduction into a separate file.

This is a first draft but thought I'd get out a general idea of the introduction I had out as soon as possible.
I'm not sure it should have a comma. Though I do think that 'of the smartphone' should be removed. As well as 'what is done and'. Finally 'gets' should be 'is'.