Next content push

- changed .gitignore for art folder
- add gulp processing for art
- changed nunjucks templates file structure to reflect demo files
- removed file for new styles
- renamed most sass variables
- added sass function for space classes
- great progress with content of the intro page
- moved old gulp tasks to DEPRECATED.md

source/style/demo_basic.scss

@@ -12,5 +12,3 @@
 // -----------------------------------------------------------------------------
 @import "modules/demo/demo_module";
 // @import "modules/YOUR-MODULE/YOUR-FILES";
-// New
-@import "demo_new";