Option to choose grid gutter type.

The work done in here when complete will allow the user to choose between ```padding``` or ```margin``` for their grid gutter type.

This pull request resolves #3.

- [x] - Add default configuration variable.
- [x] - Add the padding/margin option for the **full** grid type.
- [x] - Add the padding/margin option for the **center** grid type.
- [x] - Add the padding/margin option for the **right** grid type.
- [x] - Add the padding/margin option for the **left** grid type.
- [x] - Add documentation to the readme.md about the new option.
- [x] - Update the configuration files for the example templates with a default configuration variable.
- [x] - Update the scaffolding configuration file so it has a default configuration variable.
- [x] - Bump version number.