Initial work on the WBT parser and its test suite

test/test_parse_invalid_character_expression.wbt

@@ -0,0 +1,6 @@
+<html>
+    <body>
+        <h1>Hello World</h1>
+        <p>{{ INVALID { EXPRESSION }}</p>
+    </body>
+</html>

test/test_parse_no_expressions.wbt

@@ -0,0 +1,5 @@
+<html>
+    <body>
+        <h1>Hello World</h1>
+    </body>
+</html>

test/test_parse_single_expression.wbt

@@ -0,0 +1,6 @@
+<html>
+    <body>
+        <h1>Hello World</h1>
+        <p>{{ VALID EXPRESSION }}</p>
+    </body>
+</html>

test/test_parse_unclosed_expression.wbt

@@ -0,0 +1,6 @@
+<html>
+    <body>
+        <h1>Hello World</h1>
+        <p>{{ INVALID EXPRESSION }</p>
+    </body>
+</html>