Debugger: Add interface for expression evaluation.

SourceLanguage:
- Add a virtual to the language base class that requests expression
  evaluation.

src/apps/debugger/source_language/SourceLanguage.cpp

@@ -1,5 +1,6 @@
 /*
  * Copyright 2009, Ingo Weinhold, [email protected].
+ * Copyright 2014, Rene Gollent, [email protected].
  * Distributed under the terms of the MIT License.
  */
 
@@ -20,8 +21,16 @@ SourceLanguage::GetSyntaxHighlighter() const
 
 
 status_t
-SourceLanguage::ParseTypeExpression(const BString &expression,
+SourceLanguage::ParseTypeExpression(const BString& expression,
 	TeamTypeInformation* info, Type*& _resultType) const
 {
 	return B_NOT_SUPPORTED;
 }
+
+
+status_t
+SourceLanguage::EvaluateExpression(const BString& expression,
+	Value*& _resultValue)
+{
+	return B_NOT_SUPPORTED;
+}