Update gems, enable sass-globbing

directory_watcher not updated due to constant
high cpu usage from frequent fs updates.

rake explicitly set to ~> 10.0.0
Laid out style sheets to match other projects
Split custom/_styles.scss into 'styles' folder
Enable use of sass/plugins folder
Increase size of text in code block
Added/updated custom asides
Add youtube embed video plugin
Smaller sidebar item bottom padding