Add multi-configuration example.

Allows user to create one configuration that outputs more than one file with different configs

examples/multi_configuration.groovy

@@ -0,0 +1,34 @@
+/**
+ * This example shows how to use the same configuration file to generate two
+ * files with different columns!
+ * This allows you to generate a set of related files with one configuration.
+ * 
+ * java -jar zefaker.jar -f=multi_configuration.groovy -output=dummy
+ */
+
+// number of rows to create in the first file
+maxRows = 10
+// the name of the first file to output
+outputFile = "companies.xlsx"
+// column configuration for the first file
+generateFrom([
+    (column(index= 0, name="Account No.")): { faker -> faker.number().numberBetween(1, 200) },
+    (column(index= 1, name="Company Name")): { faker -> faker.name.fullName()  + faker.options().option("Plc", "Pvt Ltd", "") },
+    (column(index= 2, name="TPIN")): { faker -> "TPIN" + faker.number().numberBetween(1, 200) },
+    (column(index= 3, name="Registration Date")): { faker -> "197001-01" },
+    (column(index= 4, name="Postal Address")): { faker -> "P.O. Box 123" },
+    (column(index= 5, name="Telephone")): { faker -> "265999" + faker.number().numberBetween(111111, 999999) }
+])
+
+// number of rows to create in the second file
+maxRows = 10
+// the name of the second file to output
+outputFile = "directors.xlsx"
+// column configuration for the second file
+generateFrom([
+    (column(index= 3, name="Company Account No.")): { faker -> faker.number().numberBetween(1, 200) },
+    (column(index= 0, name="Full name")): { faker -> faker.name.fullName() },
+    (column(index= 1, name="Phone Number")): { faker -> "265999" + faker.number().numberBetween(111111, 999999) },
+    (column(index= 2, name="E-mail")): { faker -> "[email protected]" },
+    (column(index= 4, name="Address")): { faker -> "P.O. Box 123" }
+])