Add an animation timeout (#659)

* added animation timeout

* Updated animation timeout to u12

* updated config comment to reflect the new range for animation timeout

res/config.ini

@@ -4,6 +4,11 @@
 # matrix -> CMatrix
 animation = none
 
+# Stop the animation after some time
+# 0 -> Run forever (default)
+# 1..2e12 -> Stop the animation after this many seconds
+animation_timeout_sec = 0
+
 # Format string for clock in top right corner (see strftime specification). Example: %c
 # If null, the clock won't be shown
 clock = null