this should be handled by #520

Instead of using fields, we will now use properties (that must have a setter).

This allows users to flag a field with InjectAttribute, and when the module is created at runtime, this field will be filled in with the object from the dependency map.

Allow commands to use added type readers

A.K.A. "FiniteReality is a twat"

Parameter preconditions and typereader overriding

Resolves #302

Fix case insensitive commands forcing parameters to return lowercase

Nickname changes/role changes are no longer sent over PRESENCE_UPDATE, making it obsolete to check for changes there.

Fixed async method

CheckPermissions was not set to async so await would not work.

Fixed Install -> commands.LoadAssembly

await commands.LoadAssembly(Assembly.GetCurrentAssembly(), map);
->
await commands.AddModulesAsync(Assembly.GetEntryAssembly());

Fixed HandleCommand Error message

if (!result.IsSuccess)
    await msg.Channel.SendMessageAsync(result.ErrorReason);
}
msg -> context

*facepalm*

This commit also adds a TypeReaders property to CommandService, so
it is possible to see all of the registered TypeReaders. This makes
it possible for users to implement their own parsing instead of
using the built-in parsing.

Seems I missed this originally, whoops.

The previous name was causing some confusion

EmbedBuilder.WithImageUrl() now uses the value passed

Add TimeSpan TypeReader