Merge pull request #43 from tiffany352/unicode-minus-sign

Parse U+2212 as minus sign (Fixes #33)

src/text_query.rs

@@ -123,6 +123,7 @@ impl<'a> Iterator for TokenIterator<'a> {
                 },
                 _ => Token::Minus
             },
+            '\u{2212}' => Token::Minus,
             '/' => match self.0.peek() {
                 Some(&'/') => loop {
                     match self.0.next() {

tests/query.rs

@@ -569,3 +569,8 @@ fn test_formula() {
     );
     test("C60", "C60: molar_mass = 0.72066 kilogram / mole");
 }
+
+#[test]
+fn test_unicode_minus() {
+    test("\u{2212}10", "-10 (dimensionless)");
+}