Fix #53

This puts through a simple fix for escaping strings.  Basically, a string
literal which contained escaped characters was not being properly escaped when
printed.

src/main/java/wyjs/io/JavaScriptFilePrinter.java

@@ -326,8 +326,9 @@ private void writeArrayLength(int indent, JavaScriptFile.ArrayLength term) {
 	private void writeConstant(JavaScriptFile.Constant term) {
 		Object value = term.getValue();
 		if(value instanceof String) {
+			String s = (String) value;
 			out.print("\"");
-			out.print(term.getValue());
+			out.print(s.replace("\"","\\\"").replace("\n","\\n").replace("\t","\\t"));
 			out.print("\"");
 		} else if(value instanceof Byte){
 			byte b = (Byte) value;

tests/valid/JsString_Valid_17.whiley

@@ -0,0 +1,7 @@
+import string from js::core
+
+public export method test():
+    // generate normal string
+    string s = "hello\n\t\"hello\""
+    //
+    assert s == "hello\n\t\"hello\""