TunnelAudio: Fixes playback with Qualcomm tunnel audio for players which use gapless api

TunnelAudio player in its current stage shows an very odd behavior.
It plays one song over DSP processor and the next is played with software decoding.

This is because there are two open instances of awesomeplayer at all time.
At the moment awesomeplayer checks at the creation if DSP processor if free, if not it falls back to software.

This patch fixes that by delaying that check to the actual call of play() so,
that the awesomeplayer which currently holds the DSP processor can free it. This is also done earlier than before.

At the moment I can only test this patch on an Sony Xperia Z
and I would really like if someone could help and test it further.

PS2: Disabled delayed codec initialization for HTTPStreaming and fixed VideoSize not notifyed
PS3: actually added changed files, sorry
PS4: White spaces fixed
PS6: Added guard in seek if codecs are initialized, check if tunnel is supported before delaying and
     if DSP is already in use.
PS7: Added missing #ifdef

Change-Id: I1bdb2351aef300778a3375cc06e048dba455121e