Adapter refactoring

This is major refactor release.

Each browser shim now has it's own file (chromeShim, edgeShim etc), the shimmed API's has explicit methods (shimGetUserMedia etc) and shared logic is put in a utils.js file. Also, it can used as a commonJS/requireJS module or instead use the browserified artifacts.

The browser selection logic is in handled in adapter-core.js.

This should make it easier to make changes and adding more browser shims in the future.

One caveat, It's not thoroughly tested with other modules, please let us know if it doesn't work together with some modules.