Chart Dates: Part 1 of 3

An update to allow users to define a specific date
range for a chart on the home window. This update
only applies to the LTM chart and only allows a
date range from/to to be defined.

It would be nice to also support a last 'n' 'period'
selection too (i.e. last n days/weeks/months).

Also, further updates are required to add similar
functionality to TreeMap, CP, Dist and Summary charts
when they are on the home window.
Chart Dates: Part 2 of 3

Updated LTM chart date range to allow the
user to specify a number of alternative
ranges;

- use current selected
- use current selected thru today
- between x and y
- last n days/weeks/months/years
- from - today
Chart Dates: Part 2 of 3 fixup

Refactor of the date settings into its own
widget so we can re-use it across any chart
that supports date ranges.
Chart Dates: refresh a bit less often

.. the plot is redrawn as the user enters a date or
number which is slow and annoying -- far better to
wait for the editingFinished() signal.
Chart Dates: Part 2 of 3 update

.. added a 'This' option to choose a date range
such as this month, week, year. I also added the ability
to specift a 'prior' period.

So in July you could plot for this month prior 1 to choose
a date range for June.

This allows folks to have a static setup of charts for this
this-1 and this-2 months and data to change over time.
accidentally left in qDebug() statement
Chart Dates: Part 3a of 3

Added chart date selection to the
Treemap chart. Still need to add this
to;

- Summary
- CP
- Histogram