* Allow commands to return a Task<RuntimeResult>
This allows bot developers to centralize command result logic by
using result data whether the command as successful or not.
Example usage:
```csharp
var _result = await Commands.ExecuteAsync(context, argPos);
if (_result is RuntimeResult result)
{
await message.Channel.SendMessageAsync(result.Reason);
}
else if (!_result.IsSuccess)
{
// Previous error handling
}
```
The RuntimeResult class can be subclassed too, for example:
```csharp
var _result = await Commands.ExecuteAsync(context, argPos);
if (_result is MySubclassedResult result)
{
var builder = new EmbedBuilder();
for (var pair in result.Data)
{
builder.AddField(pair.Key, pair.Value, true);
}
await message.Channel.SendMessageAsync("", embed: builder);
}
else if (_result is RuntimeResult result)
{
await message.Channel.SendMessageAsync(result.Reason);
}
else if (!_result.IsSuccess)
{
// Previous error handling
}
```
* Make RuntimeResult's ctor protected
* Make RuntimeResult abstract
It never really made sense to have it instantiable in the first place,
frankly.
74f6a4b392