core: removed debug messages from z_media_tag.
mod_base: controller_websocket's dispatch arguments were discarded

This prevented the example in the documentation from working.
http://zotonic.com/docs/0.9/ref/controllers/controller_websocket.html
mod_base: Websocket handle_message callback now gets the 'From' pid.

Previously it was not possible to send a message back to the websocket
in a custom websocket handler's `websocket_message` function, because
the pid of the websocket sender process was not known. This commit
fixes that by propagating the pid of the send loop into the
handle_message function.

This introduces a backward incompatibility with any custom websocket
handlers.
core: Fix in Zotonic after removing access to the webmachine_request:send_response/2 function
Merge pull request #613 from yoonka/fix-crash-in-perf-logs

core: Fix in Zotonic after removing access to the webmachine_request:send_response/2 function

Needed due to merging pr zotonic/webzmachine#12: https://github.com/zotonic/webzmachine/pull/12
core: Fix .ogg/.ogv to be correctly identified as audio/video.

The "file" utility classified both of these types just as
"application/ogg", which is to broad.