Attempt to script the Devotion Ability for White Mage

Hi. First time contributor =) 

I was playing around with the Darkstar software because it seems interesting, and I wanted to take a shot at contributing a script. I play WHM and noticed that Devotion is missing, so I took a shot at implementing it. I am new to Lua so please forgive me if I made any silly mistakes. 

I retired from FFXI in 2009, so I can't currently check this against a real server anymore. As such, I listed my implementation references below. If this looks good, I will script Martyr in another pull request since it is also missing. I've tested all the scenarios listed below and it seems to be working. Let me know if there is anything I need to adjust. 

Thanks!
-SLK

Notes:
-Converts 25% of Player's HP to MP for the target
-Merits add +5% MP recovered per merit (but HP taken stays at 25%)
-Maximum Distance is 10
-Player Cannot Cast on Self
-Stoneskin can absorb the damage if its up
-Ability fails if your HP is less than 4

References:
http://wiki.ffxiclopedia.org/wiki/Devotion
http://www.ffxivpro.com/forum/topic/36540/on-healing-hands-a-comprehensive-whm-guide/