add uwsgi provider for WSGI applications
use a single validation error handling function
add one role validation method to be used in child objects
use a validation_error method which also does logging
extend drop target to include the box of servers

Fixes bnc#838662
added methods for validating the existence of a db proposal
allow comma-separated lists as well as space separated ones
extending 'wait for chef' for other states
Merge pull request #777 from MirantisDellCrowbar/feature/uwsgi/master

[feature] add uwsgi provider for WSGI applications
timeout must be integer
remove comment from xml config
Merge pull request #799 from MirantisDellCrowbar/bug/uwsgi-config/master

remove comment from xml config
Merge pull request #798 from jsuchome/timeout

timeout must be integer
Merge pull request #787 from mapleoin/comma-split

Got +1 and was tested => merging
Merge pull request #782 from mapleoin/one-role

+1 from me; also got smoketested => merging.
Merge pull request #795 from jsuchome/wait-for-chef

Got +1 and was tested => merging.
Merge pull request #786 from mapleoin/droptarget

Got +1 and tested => merging.
Merge pull request #783 from mapleoin/find-database

Got smoketested, and +1 from me too => merging.
Try harder to ignore stale lock files

When there is a stale lock file staying around, ignore it.
Ignore pid files with invalid content

Vincent pointed out in the previous review that we
want to also ignore pid files with invalid content
(like e.g. 0 byte sized files)