CLI: daemon

[bates64]

e.g.

$ decent -p 4040 --db .
decent>
^C

$ decent start "cool server" -p 4040
decent: server "cool server" running in background

$ decent stop cool server"
decent: server "cool server" stopped

[towerofnix]

(Assigning @heyitsmeuralex so you can actually fill in the description with more info. What kind of stuff should go in the server config? How would we make this work with server properties? Would server properties be obsolete with this? Et cetera.)