Added FAQ directory under docs, with one entry

[kjmcclaning]

First time git'er, first time sphinx'er, first time a lot of things. Please point out any mistakes or errors I made.

[corranwebster]

@kjmcclaning Thanks for the contribution, and sorry for the delay in responding.

Unfortunately, the Chaco dependency makes it a poor fit for a TraitsUI example.

I think that your code would be a good fit for either a documented Chaco example in the Chaco project or, with the example suitably modified to remove Chaco, as an example for TraitsUI. I'm also not sure that we need a FAQ, but a "TraitsUI cookbook" with annotated examples would be quite valuable, I think.