Compile library with advanced closure compiler settings

[danimoh]

Might save another 10kb.

Special attention will have to be spent on the options object handed over to jsQR and the grayscaleWeigths defaults. While these are used internally only, the way they are merged together might confuse closure compiler.

Also the way typescript compiles enums is not compatible with closure compiler.

Compiling from typescript source with https://github.com/angular/tsickle might be good.

[danimoh]

Also, potentially move advanced features like rendering of scan region and barcode outline into separate, lazy loaded chunks.