Merge remote-tracking branch 'remotes/stefanha/tags/tracing-pull-request' into staging

# gpg: Signature made Mon 18 Jul 2016 22:59:55 BST
# gpg:                using RSA key 0x9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>"
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>"
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* remotes/stefanha/tags/tracing-pull-request:
  trace: Add QAPI/QMP interfaces to query and control per-vCPU tracing state
  trace: Allow event name pattern in "info trace-events"
  trace: Conditionally trace events based on their per-vCPU state
  trace: Add per-vCPU tracing states for events with the 'vcpu' property
  trace: Cosmetic changes on fast-path tracing
  disas: Remove unused macro '_'
  trace: Identify events with the 'vcpu' property
  trace: [bsd-user] Commandline arguments to control tracing
  trace: [linux-user] Commandline arguments to control tracing

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>