Logo experiments
Gravitate towards a logo solution
Update branding

Adds new logo and favicon
Changes any references to "Insight Charts" to "InsightJS"
Removes the jumbotron
Use image logo, not text

Uses our new banner logo as the main logo on the front page.
Also creates a new mini-icon logo
Move styling into css

Removes the inline styles in favour of style.css

The logo is now smaller and more padded, and we have removed some unused
tags
Merge pull request #119 from tpkelly/gh-pages

New logo branding
Merge branch 'gh-pages' of https://github.com/ScottLogic/insight into gh-pages