This patch fixes the Usage string for a call message
that isn't matched by any plugin.
Plugin object now must impleent a 'command_name' attribute
that is the usage string for that plugin.
This patch adds the new APRSD Command Plugin architecture.
All Comand plugins must implement the same object API, which includes
plugin object is subclass of APRSDPluginBase
version attribute
command_regex attribute
command method
When an APRS command is detected, then the regex is run against
the command. If the command_regex matches, then the plugin's
command() method will be called. If the command() method returns
a string, then that string is sent as a reply to the APRS caller.
A new aprs.yml config section is added to support selecting
which plugins to enable.
If you want all plugins enabled, then omit "enabled_plugins" entirely
from the aprs section of the config.
To load custom plugins:
1) create a directory with an __init__.py file
2) Add a plugin.py file that contains your plugin
Look at the exmaples directory for an example plugin.
