Add support for multiline aliases

[pradyunsg]

Not that I want it but someone might someday. If so, this should be added.

Or if someone _me feels bored and wants to extend this project.

[djui]

Good. Also see: https://github.com/djui/alias-tips/blob/master/alias-tips#L34

[pradyunsg]

Closing this out, since looks like no one wants this. :)