Use better defaults that match modern style

[guzart]

• Better es6 template New release with es6? #34
• Use a different JSON.stringify that outputs the constants values (single quotes) Lint warnings/errors on generated constant module #24 Add ability to disable jscs on constant file #26
• Add strict template for angular 1? Isolate scope for constant template #36
• Add path option to extract the values from a given path
• Add environment variable that internally uses path