Added voicing/devoicing commands. Allow recipient parameter for "cocoa" command.

Added ability to voice/devoice users with the same parameter and permission requirements as op/deop. The "cocoa" command allows a nick to be included as a parameter to act as the recipient instead of the user who invoked the command.
Added a "lag" command.

Added a "lag" command to allow users to quantify their lag. It simply sends a /CTCP PING to the user and processes the reply. Changed processPrivateCommand() to processPrivateMsg().