Refactor MainWindow Part 2 of 5

Decoupled classes from MainWindow to reference Context
and Athlete (and introduced a couple of new headers).

We no longer pass around a MainWindow pointer to children
but pass a context instead.

There are still a few pieces left in MainWindow that need
to move to a better place;
    * Setting/clearing filter selection
    * Working with Intervals
    * Adding/Deleting Rides
    * Save on Exit

As mentioned previously there are lots of other parts to
this refactor left to do;
    * break MainWindow Gui elements into Toolbar and Views

    * migrate from RideItem and Ridelist to ActivityCollection
      and Activity classes that are not tied into gui elements.

    * introduce Application Context and AthleteCollection

src/HelpWindow.cpp

@@ -17,18 +17,16 @@
  */
 
 #include "HelpWindow.h"
+#include "MainWindow.h"
 
-#include <QDebug>
-
-
-HelpWindow::HelpWindow(MainWindow *mw) : QDialog(mw)
+HelpWindow::HelpWindow(Context *context) : QDialog(context->mainWindow)
 {
     setWindowTitle("Help");
     setAttribute(Qt::WA_DeleteOnClose);
     setWindowFlags(windowFlags() | Qt::WindowStaysOnTopHint | Qt::Tool);
     setInstanceName("Help Window");
 
-    parent = mw;
+    //XXX ???? parent = context->mainWindow;
     view = new QWebView();
     layout = new QVBoxLayout();
     layout->addWidget(view);