toaster: allow setEventMask to be called by bitbake observer

This patchset is a preparation for the #7880 fix. This will allow the toasterui to work in build mode, i.e. with bitbake <target> -u toasterui.

If you want to test this functionality you can do the following:
- start Toaster
- kill bitbake server and observer processes
- unset BBSERVER
- add INHERIT+="toaster buildhistory" line to conf/local.conf
- run bitbake <target> -u toasterui

Expected outcome: you should see commandline build in UI without bitbake server
and observer running.

Also, I've discovered nasty bug in handling setEventMask by bitbake server while working on this. It causes ignoring of the event mask set by toasterui. The result of this is that list of events in _ev_list variable is different from the actual list of events processed by toasterui.

Upstreamed for Ed,
-bavery

The following changes since commit ffce6a18876c3a0c949eb75f0ce2f9dc36054c83:

toaster: remove sshbecontroller module (2016-03-02 20:31:08 -0800)

are available in the git repository at:

git://git.yoctoproject.org/poky-contrib bavery/submit/ed/toaster/toasterui-in-build-mode
http://git.yoctoproject.org/cgit.cgi/poky-contrib/log/?h=bavery/submit/ed/toaster/toasterui-in-build-mode

Ed Bartosh (7):
toasterui: reformat list of events
toasterui: update list of events
command: make setEventMask readonly
toasterui: check if setEventMask succeeded
toasterui: make toasterui to work in build mode
toasterui: exit on final events
toasterui: fix warning 'Unknown event'

 lib/bb/command.py      |  1 +
 lib/bb/ui/toasterui.py | 90 +++++++++++++++++++++++++++++++++++---------------
 2 files changed, 64 insertions(+), 27 deletions(-)

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1.9.1