The treemap chart was developed as a variation of an LTM
chart and as a results has the same chart settings etc.
It has now been refactored to be a standalone chart with
no need to re-use the LTM settings and code.
This is also in preparation to support click through on
the cells to show a popup of rides.
Lots of nitty fixups, largely for uninitialised temporary
variables.
I have left the use of boost::function and boost::bind in the
DownloadRideDialog alone, so it will vomit when compiled
with boost 1.46 and gcc 4.5 or higher. Will look into this
more carefully at a later stage.
I am working up to resolving issues identified from -pedantic next.
The recent fix for date range selection was not applied to the
TreeMap plot and caused a SEGV on restart (when placed on home
window). This fixes that.
It also fixes a minor cosmetic related to QFrame margins.
