Allow for external interactions with current runtime

[lipkau]

Expected Behavior

External command can take influence on the a2 runtime. Examples:

• Context Menu can send command to module
• URI Schema can send command to runtime

Current Behavior

n/a

Possible Solution

• [ ] #SingleInstance Off --> so that a second instance can be opened, which will send a message to the already running instance and then close itself
• [ ] register OnMessage(55555, "TriggerFromOtherInstance") --> make instance listen to triggers
• [ ] register OnExit() to reload the instance nicely (A_ExitReason == "reload")

[lipkau]

in implementation in https://github.com/ewerybody/a2/tree/feature/AllowExternalCalls

[ewerybody]

Dang I was unaware of the improvements in the branch. :O

I now added handling of arguments. So --shutdown works already... Still I'd actually like the a2 runtime to be as dumb as possible, let the UI do the heavy lifting and make anything else possible with the modules.

In a way I could think of dealing with the whole thing through the commandline. Like enabling modules, update things ... But that all would just configure and reload the runtime. I'd need an example for what the runtime needs to perform.