Add a new command /jail time which has easy access for add/subtract

time from a prisoner's sentence.

This command could be useful for commandblocks or something else, as it
does not need a player context. This closes Bukkit Dev Ticket:
http://dev.bukkit.org/bukkit-plugins/jail/tickets/432/

src/main/resources/en.yml

@@ -58,6 +58,7 @@ language:
     nowunmuted: '&9%0% is now unmuted.'
     offlinejail: '&2%0% is offline and will be jailed when they next come online for %1% minutes.'
     onlinejail: '&2%0% was jailed for %1% minutes.'
+    prisonerstime: '&2%0% has %1% minutes remaining.'
     protectionmessage: '&c%0% minutes have been added to your time for %1%.'
     protectionmessagenopenalty: '&cProtection enabled for %0%, do not do it again.'
     provideaplayer: '&cPlease provide a player when %0% &cthem.'