Refactor the accesors to behave like methods instead of properties.
This means all accesors will be prepended with the string
"get_" and will include a set of parenthesis.
Improve the ModeAttribute class to use the method's
short_description. This commit also adds support for a
new method .help_text attribute has been added.
Move accessors to their own module, named "methods.py".
Remove the PropertyHelper class as the accessors no longer
need it.
Signed-off-by: Roberto Rosario <Roberto.Rosario@mayan-edms.com>
