Subject: Core

Added debug logging categories that allow a user to output debug information
based on a specified category. This lets the user limit, and filter debug
output to data relevant to a particular context, or topic. For instance the
following categories are now available for debug logging purposes:

  dtls, dtls_packet, ice, rtcp, rtcp_packet, rtp, rtp_packet, stun, stun_packet

These debug categories can be enable/disable via an Asterisk CLI command:

  core set debug category <category>[:<sublevel>] [category[:<sublevel] ...]
  core set debug category off [<category> [<category>] ...]

If no sub-level is associated all debug statements for a given category are
output. If a sub-level is given then only those statements assigned a value
at or below the associated sub-level are output.

