make it clearer what is being returned

src/lexer.cpp

@@ -56,10 +56,10 @@ int obelisk::Lexer::getToken()
 
         if (getIdentifier() == "extern")
         {
-            return kTokenExtern;
+            return Token::kTokenExtern;
         }
 
-        return kTokenIdentifier;
+        return Token::kTokenIdentifier;
     }
 
     if (isdigit(lastChar))

src/lexer.h

@@ -81,22 +81,26 @@ namespace obelisk
                  *
                  */
                 kTokenFact = -2,
+
                 /**
                  * @brief A rule which is a relationship between a new fact a
                  * existing fact.
                  *
                  */
                 kTokenRule = -3,
+
                 /**
                  * @brief An action to take if a fact is true.
                  *
                  */
                 kTokenAction = -4,
+
                 /**
                  * @brief A definition of a new function.
                  *
                  */
                 kTokenDef = -5,
+
                 /**
                  * @brief An external function that will be linked to.
                  *
@@ -108,11 +112,13 @@ namespace obelisk
                  *
                  */
                 kTokenIdentifier = -7,
+
                 /**
                  * @brief A double floating point value.
                  *
                  */
                 kTokenNumber = -8,
+
                 /**
                  * @brief A string.
                  *