Updates and Fixes to Epstein Civil Violence Model

[JoeHelbing]

This is my first public repository issue/pull request. I had mentioned I made these changes a few months ago, but haven't had time until now after the school year is over to clean it up and organize it for a pull request.

These changes fix the lack of cyclical explosions in Citizen agent behavior in the mesa Epstein Civil Violence model with a few tweaks.

Bug Fixes

• Fix agent state logic
• Fix Moore vs Von Neuman neighborhood selection to use Epstein paper behavior
• Fix agent vision bug (was 1 and not parameter vision when calculating neighborhood, which also fixes agent movement issue)
• Fix arrestee state issue (arrestee was not being reset to "Quiescent", and so was counting as "Active" for all nearby agents)

Additions and Changes

• add model attributes to count agents and display a graph of agent states
• Change display of agents where jailed agents are represented by grey square box
• Added sliders for model attributes