Refactor Perfdata things into pynag.Utils.metrics
Refactor GitRepo into its own module Utils.git
Refactor PynagError into Utils.errors
Refactor send_nsca into Utils.nsca
Clean up imports and linebreaks in Utils
Refactor synchronized and cache_only to decorators
Clean up imports and ordering in Utils
Refactor reconsile_threshold into Utils.metrics

+ Minor fixes
Move errors.py to top-level
Refactor reconsile_threshold>new_threshold_syntax

This function belongs there because it only supports
the new threshold syntax.

Also renamed to more approprately 'convert_to_classic_format'
Fix broken imports for errors module
Explicitly import PynagError

This is needed because there are still unresolved cross-imports
in pynag and explicitly importing PynagError fixes parts of the code
that Utils was import but at the same time those modules were doing:

'from pynag.Utils import PynagError'

This refactor, and a few other changes will make it possible for
us to get rid of those cross imports.
Refactor use of PynagError in Control
Refactor use of PynagError in Command
PynagError: Fix call to super

Call to super was errounously done as self.__class__ instead
of explicitly saying 'PynagError'.

This lead to recursion errors when multiple levels of subclassing
this error.
Refactor PynagError in the Utils package

All modules that raise error now have their
own exception that inherits PynagError.
Refactor PynagError in the Plugins package

All modules that raise error now have their
own exception that inherits PynagError.
Exception handling in Parsers improved

* All exceptions moved to the top of the file
* ParserError now inherits from PynagError instead of Exception
Unify exception handling in Model

Exceptions that previously raised PynagError now all
raise a subclass of PynagError instead.
Minor fixes after running pyflakes