Commands can be overridden by users

#### Description

When a user has for nick a name that's also a command they can overwrite the command.
#### Expected Behavior

```
<swag>: !swag Hello World
<gbot>: out of ten!
<swag>: !swag
<gbot>: out of ten!
```
#### What actually happens

```
<swag>: !swag Hello World
<user>: !swag
<gbot>: Hello World
<swag>: !swag
<user>: !swag
(no response from gbot)
```
