Solved issue #61 - Add sourcemap for webpack

[stablexbt]

Source map is added to webpack

• The Webpack devtools are set to generate sourcemap.
• 2/2 webpack function files were modified to add devtools functionalities.
• Errors will be displayed with line numbers of original files, hence easing down debugging.
• Devtool setting can be changed from "source-map" to "eval-source-map" for faster development and testing purposes.

Tried to fix all of Travis CI Eslint problems only to realize that fixing "Cyclomatic complexity" issues really disturbs the integrity of our classes and is not worth the trouble. Maybe we will increase the min. limit if required.