Added new special operators like &= and <<=.

Also made a litle change to scanner function moveOn(): now it moves on
the last char passed and only if there are more than one chars.

t_strings_test.go

@@ -9,6 +9,7 @@ import (
 )
 
 func TestStringsParser(t *testing.T) {
+	section := "String"
 	inputs := []inputType{
 		/*  1 */ {`"uno" + "due"`, `unodue`, nil},
 		/*  2 */ {`"uno" + 2`, `uno2`, nil},
@@ -22,6 +23,6 @@ func TestStringsParser(t *testing.T) {
 		/* 10 */ {`"AF3B0Dz" / 0`, nil, "[1:12] division by zero"},
 	}
 
-	// runTestSuiteSpec(t, "String", inputs, 8)
-	runTestSuite(t, "String", inputs)
+	// runTestSuiteSpec(t, section, inputs, 8)
+	runTestSuite(t, section, inputs)
 }