game engine, tests and other fixes:

tests: fixed wrong permanent structure for battlefield cards (addCard command);
tests: added docs and additional runtime checks;
game: Modal double-faced cards - improved support, no more other side effects on battlefield;
game: Copy abilities - improved stability and cards support;
game: Player under control - improved stability and related cards support (possible NPE errors, additional runtime checks);
server: fixed bloated logs with game timer;
AI: fixed wrong timer in computer games;

Mage/src/main/java/mage/players/Player.java

@@ -294,10 +294,8 @@ public interface Player extends MageItem, Copyable<Player> {
     void setTopCardRevealed(boolean topCardRevealed);
 
     /**
-     * Get data from the client Preferences (e.g. avatarId or
-     * showAbilityPickerForce)
-     *
-     * @return
+     * User's settings like avatar or skip buttons.
+     * WARNING, game related code must use controlling player settings only, e.g. getControllingPlayersUserData
      */
     UserData getUserData();
 
@@ -333,6 +331,9 @@ public interface Player extends MageItem, Copyable<Player> {
 
     List<UUID> getTurnControllers();
 
+    /**
+     * Current turn controller for a player (return own id for own control)
+     */
     UUID getTurnControlledBy();
 
     /**
@@ -360,6 +361,11 @@ public interface Player extends MageItem, Copyable<Player> {
      */
     void setGameUnderYourControl(boolean value);
 
+    /**
+     * Return player's turn control to prev player
+     * @param value
+     * @param fullRestore return turn control to own
+     */
     void setGameUnderYourControl(boolean value, boolean fullRestore);
 
     void setTestMode(boolean value);