Implement ES6 Template Literals

src/messages.js

Index: src/messages.js
diff --git a/src/messages.js b/src/messages.js
index 8a4e5e81cb3ad3f0fe94eebf9ff6a6886d9c2787..8472454a37c4d99d550e1482f61a62b0559cfb48 100644
--- a/src/messages.js
+++ b/src/messages.js
@@ -18,9 +18,12 @@ var kMessages = {
   unexpected_reserved:           ["Unexpected reserved word"],
   unexpected_strict_reserved:    ["Unexpected strict mode reserved word"],
   unexpected_eos:                ["Unexpected end of input"],
+  unexpected_template_string:    ["Unexpected template string"],
   malformed_regexp:              ["Invalid regular expression: /", "%0", "/: ", "%1"],
   malformed_regexp_flags:        ["Invalid regular expression flags"],
   unterminated_regexp:           ["Invalid regular expression: missing /"],
+  unterminated_template:         ["Unterminated template literal"],
+  unterminated_template_expr:    ["Missing } in template expression"],
   regexp_flags:                  ["Cannot supply flags when constructing one RegExp from another"],
   incompatible_method_receiver:  ["Method ", "%0", " called on incompatible receiver ", "%1"],
   multiple_defaults_in_switch:   ["More than one default clause in switch statement"],