Instrument pyramid

[andrewslotin]

This PR adds instrumentation for apps written with Pyramid framework. Please note, that it does not support auto-instrumentation yet and requires manual activation by including the following line into the configuration section of your app (the main function):

with Configurator(settings=settings) as config:
    # ...
    config.include('instana.instrumentation.pyramid.tweens')
    # ...

In case you have the pyramid.tweens option set in your production.ini config, make sure that instana.instrumentation.pyramid.tweens.InstanaTweenFactory is the first entry in this list:

pyramid.tweens = 
    instana.instrumentation.pyramid.tweens.InstanaTweenFactory
    # other tweens