feat(index): export interfaces

Author: kwonoj

src/index.ts

@@ -1,2 +1,7 @@
 export { log, enableLogger } from './util/logger';
 export { OutputStyle, SassOptionsInterface } from './interop/options/sassOptions';
+export { loadModule } from './loadModule';
+export { SassFactory } from './SassFactory';
+export { SassContextInterface } from './interop/sassContext';
+export { SassSourceContext } from './interop/SassSourceContext';
+export { StringMethodInterface } from './interop/interopUtility';