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

# gpg: Signature made Wed 01 Feb 2017 13:44:32 GMT
# 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: clean up trace-events files
  qapi: add missing trace_visit_type_enum() call
  trace: improve error reporting when parsing simpletrace header
  trace: update docs to reflect new code generation approach
  trace: switch to modular code generation for sub-directories
  trace: move setting of group name into Makefiles
  trace: move hw/i386/xen events to correct subdir
  trace: move hw/xen events to correct subdir
  trace: move hw/block/dataplane events to correct subdir
  make: move top level dir to end of include search path

# Conflicts:
#	Makefile

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