Support scalar expressions for constants

This allows ReflectionConstant to parse scalar expressions when defining
constants, such as:

    const FOO = 1 ** 2;
    const BAR = array(1 => 'one');
    const BAZ = 'foo' . 'bar';
    const QUX = \Acme\Com\Demo::class;

Should fix Andrewsville#62 and Andrewsville#69.

TokenReflection/ReflectionConstant.php

@@ -343,12 +343,21 @@ private function parseValue(Stream $tokenStream, IReflection $parent)
 		static $acceptedTokens = array(
 			'-' => true,
 			'+' => true,
+			'(' => true,
+			')' => true,
+			'[' => true,
+			']' => true,
+			'.' => true,
 			T_STRING => true,
 			T_NS_SEPARATOR => true,
 			T_CONSTANT_ENCAPSED_STRING => true,
 			T_DNUMBER => true,
 			T_LNUMBER => true,
 			T_DOUBLE_COLON => true,
+			T_POW => true,
+			T_ARRAY => true,
+			T_DOUBLE_ARROW => true,
+			T_CLASS => true,
 			T_CLASS_C => true,
 			T_DIR => true,
 			T_FILE => true,