Fix build: add excludes/ignores and bundle generation
Fix build: add excludes/ignores and bundle generation

For some reason browserify complained about mdns, which definitely is not
needed in browser environment. Ws has bufferutil and utf-8-validate as
optional dependencies, but browserify fails on them, so ignore them.
See https://github.com/websockets/ws/issues/659.
Fix also bundle generation, the pipe looks like a bug or some
shell specific feature(?). This produces 3.5M bundle.js.

SignalK/freeboard-sk,SignalK/freeboard-sk,joabakk/freeboard-sk,joabakk/freeboard-sk,SignalK/freeboard-sk