Add SCSS generating

[huynhsamha]

I've add an entry file files/assets/scss/style.scss to generate file files/assets/css/style.css. Output is generated at files/assets/scss/style.css and files/assets/scss/style.min.css.

I've changed file files/assets/css/style.css with file files/assets/scss/style.min.css and the template is also working well.

You can merge this pull request to anyone who want to custom colors of template by using SCSS generating.

Thank for your review!

[jovipac]

Thank you, for your support to improve the code