Updates to joined.erb

Based on [this conversation](https://github.com/exercism/exercism.io/issues/1618#issuecomment-48494051), here is a framework for the verbiage.
Wordsmith on About page

This may benefit from some fancy styling.  And I am not purporting this is yet perfect.

Katrina: I respect your words (at the bottom) to tell __your story__ and only made a few changes that, in my opinion, made it 'read' a bit smoother.
Improved the wordplay on Exercism

It required a bit of a search but I located [Meliorism](http://www.thefreedictionary.com/meliorism) in order to [admittedly 'force'] the play on Exercism as Exercises that make you a better coder.
Merge pull request #1658 from ParkinT/wordplay