Fixes Klutz Mishaps Permanently Jamming Guns (#79)

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Addresses the bug listed in Issue #66. 

## About The Pull Request
Added a reset to a gun's currently_firing variable just before the klutz
fuckup return, allowing guns that are mishapped by klutzes to be fired
again without having any other impact on the way that guns work.


## Changelog
fix: Klutz mishaps no longer permanently break guns. 

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code/modules/projectiles/gun.dm

@@ -620,6 +620,7 @@ For the sake of consistency, I suggest always rounding up on even values when ap
 				user.drop_item()
 		else
 			handle_click_empty(user)
+		currently_firing = FALSE	//Add this here or else people who have clumsy will permanently break guns and prevent them from firing if they fuck up with it.
 		return FALSE
 
 	currently_firing = FALSE