* EventCallback object have order
* callbacks are processed by the callback order
* safer approach to get function information
* modified docstring a little
* added tests for ordered calbacks
* fix python 2 support
* added support for partial methods
* removed unused '_get_func_info'
* formatting fix
* change test functions docstring
* added test for removement of source function when partial is used
* Allow order 'None'
* implemented 'weakref_partial' to allow partial callbacks
* minor tweaks
* added support to pass additional arguments to 'wearkref_partial'
* modify docstring
* added 'weakref_partial' to tests
* move public method before prive methods
* added required order back but use '100' as default order
* fix typo
Co-authored-by: Roy Nieterau <roy_nieterau@hotmail.com>
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Co-authored-by: Roy Nieterau <roy_nieterau@hotmail.com>
* implemented 'is_func_signature_supported' function
* 'WeakMethod' can be imported from 'python_2_comp' all the time
* simplified events logic for callback registration
* modified docstrings in publish lib
* removed unused imports
* fixed 'run_openpype_process' docstring
