[WIP] Multiple buffers

Created by: wesleywiser

Related to #24 (closed)

Here's what's currently implemented:

• Support for multiple buffers
• o file opens the file in a new buffer
• ls lists the available buffers in a new buffer
• b{n} switches to the specified buffer

I still need to:

• Update help.txt
• Add bd to remove the current buffer

I'd appreciate feedback on the code and\or the features.

Thanks!