Added plugin: NPO (Nederlandse Publieke Omroep)
Plugin NPO: minor cleanup.
Plugin NPO: separated metadata function + added user-agent headers.
Plugin veetle: fix streams for shorturls.
Connectcast plugin: work around json parse error.
Merge pull request #599 from monkeyphysics/npo-plugin

Added plugin: NPO (Nederlandse Publieke Omroep)
Merge pull request #601 from monkeyphysics/veetle-fix-shorturls

Plugin veetle: fix streams for shorturls.
Merge pull request #602 from monkeyphysics/connectcast-fix-playlist

Connectcast plugin: work around json parse error.