plugins.nrk: Add support for NRK radio streams.
Merge pull request #433 from jantore/nrk-radio

plugins.nrk: Add support for NRK radio streams.
plugins.zdf_mediathek: Refactor to use the validation API.
cli: Make --help alot prettier and more helpful.
docs: Auto-generate the CLI options.
docs: Some minor tweaks.
plugins.ard_live: Minor tweak.
plugins.filmon: Refactor to use the validation API.
plugins.picarto: Update RTMP URL.

Resolves #431.
cli: Stricter and safer config parsing.

Resolves #432.
cli: Don't load the default config when using --config.
travis: Upload a win32 build called "latest" aswell.