ENH: Builder loops can now be identified as not "trials" (e.g for blocks)

If a loop represents the stimuli within a trial or blocks around a trial
loop then we don't want it to advance the trialwise data file nor create
new worksheets in the excel file.

Added a parameter `isTrials` to the three loop handlers to flag this
TESTS: added a test for the new option that loops!=trials
Merge pull request #692 from isolver/master

ENH: GP3 eyetracker supports sendMessage()
TESTS: removed some print statements and making test_info more robust

test_info currently fails if sys.argv[0] is not a valid file which can
occur if
	a) other arguments are on the command call
	b) the argv[0] is a relative path and our cwd has changed
So now we check whether test_info is a valid file path before trying to
use it
Merge pull request #690 from peircej/master

Option to flag a Builder Loop as not being trials (e.g. might be blocks or stimuli)
FF: the window id from pyglet was wrong on some systems

We (Sol) had set it to use:
  self.winHandle._nswindow.windowNumber() #pyglet 1.2
  self.winHandle._window.value #for pyglet 1.1.4
But I think it depends on 64bit python not which version of pyglet
because my pyglet tip (commit 7f99b5234f7b) under a 32bit python fails this

Using a try...except instead
FF: made the git-sha checking code more robust on win32

Reverted to using @jeremygray's code for this. The Popen code doesn't
look quite as neat as using check_output() but it seems not to fail,
which is preferable! ;-)
changelog update