Introduce namespace langutil in liblangutil directory.

Also:
- Use {}-style list initialisation for SourceLocation construction
- Introduce new system includes
- Changes the API of the Scanner to take source as value (with move) as opposed to as a reference

libsolidity/analysis/TypeChecker.h

@@ -29,13 +29,16 @@
 #include <libsolidity/ast/ASTForward.h>
 #include <libsolidity/ast/ASTVisitor.h>
 
+namespace langutil
+{
+class ErrorReporter;
+}
+
 namespace dev
 {
 namespace solidity
 {
 
-class ErrorReporter;
-
 /**
  * The module that performs type analysis on the AST, checks the applicability of operations on
  * those types and stores errors for invalid operations.
@@ -45,7 +48,7 @@ class TypeChecker: private ASTConstVisitor
 {
 public:
 	/// @param _errorReporter provides the error logging functionality.
-	TypeChecker(EVMVersion _evmVersion, ErrorReporter& _errorReporter):
+	TypeChecker(EVMVersion _evmVersion, langutil::ErrorReporter& _errorReporter):
 		m_evmVersion(_evmVersion),
 		m_errorReporter(_errorReporter)
 	{}
@@ -183,7 +186,7 @@ private:
 	/// Flag indicating whether we are currently inside a StructDefinition.
 	bool m_insideStruct = false;
 
-	ErrorReporter& m_errorReporter;
+	langutil::ErrorReporter& m_errorReporter;
 };
 
 }