update About.xml

I roughly tested this mod.
It seems working fine in 1.6

add the original mod link in the about file again

1.5

change description of about.xml

1.5 version changes and fix：
The 1.5 version of rimworld changed the useage of xml tag<skillGive>
Most <skillGive>used in backstore of pawn.
You can learn how to use the new way in backstories def.

old example:<skillGive><li><key>skill<key><value>num<value></li></skillGive>

1.5 example :<skillGive><skill>num</skill></skillGive>

description change

1.4 fix：
fixed a few xml tags to 1.4 version of game
old tag -> new tag

<HungerRateMultiplier> -> <hungerRateFactor>
<ToxicSensitivity> -> <ToxicResistance> & <ToxicEnvironmentResistance>