Removed editor-style style files in favor of adding a simple _tinymce.scss partial. This cuts styles compiling time in about half.

`add_editor_style` now just references `main.css`

assets/styles/main.scss

@@ -16,3 +16,4 @@
 @import "layouts/_footer";
 @import "layouts/_pages";
 @import "layouts/_posts";
+@import "layouts/_tinymce";