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/GcCrashDialog.cpp

@@ -25,6 +25,7 @@
 #include "DBAccess.h"
 #include "MetricAggregator.h"
 #include <QtSql>
+#include <qwt_plot_curve.h>
 
 #define GCC_VERSION QString("%1.%2.%3").arg(__GNUC__).arg(__GNUC_MINOR__).arg(__GNUC_PATCHLEVEL__)