Remove unused assets

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Remove rails_layout

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Add font awesome

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Add custom variables for Bootstrap

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Add style to ideas#index page

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Add style to ideas#show page

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Add style to the form of idea page

[Issue #20] https://github.com/hutusi/ideaegg/issues/20
Add footer to layout

[Issue #20] https://github.com/hutusi/ideaegg/issues/20