player: avoid stalling when starting a network stream

Starting a network stream could stall by executing uncacheable stream
control requests (STREAM_CTRL_GET_LANG and STREAM_CTRL_GET_DVD_INFO).
Being uncacheable means the player has to wait until the cache is done
reading the current block of data. These requests can't be cached
because they're too complicated, so the only way to avoid them is
special casing the DVD and Bluray streams (which are the only things
which need these requests), and not doing them in other cases.

(This is kind of inelegant, but so is the rest of the DVD/BD code.)
player: don't print status in --idle mode

Apparently this annoys certain users. Restores old behavior.