Add rollup to build libruary.

[OperKH]

Also:

• Add .editorconfig.
• Add .prettierrc to be able quick format w/o brakiong es-lint rules.
• Add .eslintrc.js to get rid of vars.
• Move "./index.js" to "./src/index.js".

To make build just run npm run build it will create ./dist folder with 3 types of modules.

Rollup config checks eslint, transpiles ES6+ code to ES5 and uglifies code.

Without build modules I can't use this lib in my project because libraries should be distributed as ES5 code to not break compatibility with <IE11 and because we are always do not compile node_modules code.

Before this PR I saw const in my vendors.js file.

[davidmarkclements]

• Add .editorconfig.

I'm not totally against adding this, but I'm also not that interested in it – But I agree with @BridgeAR it should be a separate PR

• Add .prettierrc to be able quick format w/o brakiong es-lint rules.

This projects uses standard, (see devDependencies) - use standard --fix to reformat

• Add .eslintrc.js to get rid of vars.

why? there's nothing wrong with using vars

• Move "./index.js" to "./src/index.js".

To make build just run npm run build it will create ./dist folder with 3 types of modules.

Rollup config checks eslint, transpiles ES6+ code to ES5 and uglifies code.

Without build modules I can't use this lib in my project because libraries should be distributed as ES5 code to not break compatibility with <IE11 and because we are always do not compile node_modules code.

Before this PR I saw const in my vendors.js file.

I would rather convert all code to ES5 manually than introduce transpilation overhead.

[OperKH]

Build is more convenient for front-end projects:

1. Code already minified
2. Code 100% supported by IE11 (ES5)
3. It's able to use any type of modules, so it adds support of any bundle system on front-end projects.