Receives a string along with starting and ending delimiters and returns the part of the string between the delimiters. It also receives a beginning occurence to begin the extraction from.

Example:
string cExpression = "JoeDoeJoeDoe";
VFPToolkit.strings.StrExtract(cExpression, "o", "eJ", 2);		//returns ""

public static string StrExtract( string cSearchExpression,
	string cBeginDelim,
	string cEndDelim,
	int nBeginOccurence );