How channel hooks are invoked

Channel hooks are invoked in exactly the same way as plugins: Awasu generates a Windows INI file that contains information about the event and the path to this file is passed to the channel hook as its command-line parameter.

Channel hooks are invoked by Awasu for two reasons:

In response to an event occurring on the channel. The config file will look like this:
```
[Config]
Command=ProcessEvent
EventName=...
```
The user is sending a command to the channel hook. The config file will look like this:
```
[Config]
Command=ProcessCommand
CommandName=...
```

Global parameter values can be retrieved (by parameter name) from the [GlobalChannelHookParameters] section, instance parameter values from [ChannelHookParameters].