[apps/graph] add methods to handle function names and colors.

Change-Id: Ic11f2dd6bd9cb473b436d5e7769e2660c173c733

apps/graph/function.cpp

@@ -1,10 +1,12 @@
 #include "function.h"
 #include <string.h>
 
-Graph::Function::Function() :
-  m_name(nullptr),
+Graph::Function::Function(const char * text, KDColor color) :
+  m_name(text),
+  m_color(color),
   m_expression(nullptr),
-  m_layout(nullptr)
+  m_layout(nullptr),
+  m_active(true)
 {
 }
 
@@ -23,10 +25,6 @@ void Graph::Function::setColor(KDColor color) {
   m_color = color;
 }
 
-void Graph::Function::setName(const char * c) {
-  m_name = c;
-}
-
 Graph::Function::~Function() {
   //FIXME: Free m_text!
   if (m_layout != nullptr) {