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.

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

This fixes #304 over foxbot's PR for the same issue.

Parameter preconditions and typereader overriding

Fix case insensitive commands forcing parameters to return lowercase

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

Currently, commands are case-sensitive. This PR allows for commands to be case insensitive (which is now the default option).

Conflicts:
	src/Discord.Net.Commands/CommandService.cs

For a command to use the DefaultRunMode, it must now have it's RunMode set to RunMode.Default (this is the default value on CommandAttribute now).

This adds an (optional) CommandServiceConfig, as well as a DefaultRunMode for commands.

This resolves #368 (for commands where a RunMode is not explicitly specified, a custom default value should be used)

This is a breaking change.

Adds a precondition that requires the bot has a specified permission (Resolves #211).

Renames RequirePermission to RequireUserPermission.

This precondition will require that the invoker of the command is the owner of the bot.

This should Fix #262

This probably isn't all of them. This is what I get for copy+pasting code.

In theory this should just work, more testing is needed though

Values in ImmutableDictionaries were strings rather than enumType