Add SourcePawn as a project language

http://wiki.amxmodx.org/Introduction_to_SourcePawn

SourcePawn is the language used for Sourcemod, which is used to modify and extend games based on Valve's Source engine.

It looks mostly like C. The biggest difference is that variable declarations look different.

{{

{\\ #!c\\ new intvar;\\ new Float:floatvar;\\ decl String:uninitializedString[30];\\ }}

}