Added pcblock and checkpcblock script commands. (#3951)

* Added getpcblock and setpcblock script commands.
* Added the docs
* Added the message 'This action is currently blocked.' when the player attempts to perform the following blocked actions
* PCBLOCK_USEITEM
* PCBLOCK_SITSTAND
* PCBLOCK_NPCCLICK
* The actions blocked are saved in state.block_action
* Click to the npc returns the WORK_IN_PROGRESS message when PCBLOCK_NPCCLICK is enabled
* Blocked action and reload script.
The player will return to his/her original state after reload script.

Thanks to @aleos89, @Lemongrass3110, @secretdataz

doc/script_commands.txt

@@ -6133,6 +6133,55 @@ Examples:
 
 ---------------------------------------
 
+*setpcblock <type>{,<account ID>};
+*getpcblock {<account ID>};
+
+'setpcblock' command prevents/allows the player from doing the given <type> of action
+during the player session (note: @reloadscript also removes all <type>).
+The <type> values are bit-masks, multiples of <type> can be added to change the player action.
+
+'getpcblock' command return the bit-mask value of the currently
+enabled block flags.
+
+The available <type> are:
+	PCBLOCK_MOVE
+	PCBLOCK_ATTACK
+	PCBLOCK_SKILL
+	PCBLOCK_USEITEM
+	PCBLOCK_CHAT
+	PCBLOCK_IMMUNE
+	PCBLOCK_SITSTAND
+	PCBLOCK_COMMANDS
+	PCBLOCK_NPCCLICK
+	PCBLOCK_EMOTION
+	PCBLOCK_ALL
+
+Examples:
+
+// Make the attached player invulnerable to monster (same as @monsterignore)
+	setpcblock (getpcblock() & PCBLOCK_IMMUNE);
+
+// Prevents the attached player from attacking and using skills
+	setpcblock (getpcblock() & (PCBLOCK_ATTACK|PCBLOCK_SKILL));
+
+// Re-enables attack, skills and item use
+	setpcblock (getpcblock() & ~(PCBLOCK_ATTACK|PCBLOCK_SKILL|PCBLOCK_USEITEM));
+
+// getpcblock related checks
+	if (getpcblock() & PCBLOCK_IMMUNE)
+		mes "You are invulnerable!";
+
+	if (getpcblock() & (PCBLOCK_MOVE|PCBLOCK_SITSTAND))
+		mes "You can't walk or sit.";
+
+	if ((getpcblock() & (PCBLOCK_ATTACK|PCBLOCK_SKILL)) == 0)
+		mes "You can attack and use skills.";
+
+	if (getpcblock() & PCBLOCK_CHAT)
+		mes "You can't chat.";
+
+---------------------------------------
+
 ==================================
 |5.- Mob / NPC -related commands.|
 ==================================