Fixed some grammar mistakes in index.html
Merge pull request #430 from ogwiz2/patch-2

Fixed some grammar mistakes in index.html
Updated foreword for greater clarity

Changed line 55 to 'More importantly, you need too be a designer. There are no default styles or layouts for impress.js presentations.' in order to improve clarity about the design skills necessary to create an impressive presentation.
Merge pull request #431 from ateich/patch-1

Updated foreword for greater clarity