Flot&Highchart Bug fixes, added some features to flot

Fixes:
- Rendering of the correct labels under the correct ticks when rendering
multiple series   (series were previously mixed)
- Fix for showing a serie with an empty associated xlabel (graphs used
to freeze, now it will show '(undefined)')

- CSS fix preventing x-axis labels from rendering outside the graph area
- Fix for rendering x-axis values, in case the first serie has gaps or
no data at all. Now if the first serie has gaps or no data, all x-axis
values will still be shown

- Fixed the built in filter options
- Improved the CSS for the built-in filter
- Series constraint wasn't applied on the filter entities
- Improved data constraint when using filters

- Fixed microflow on click action, wasn’t working previously

- Fix for not rendering the chart in case of empty x-axis labels
- Improved Date positioning on x-axis, in case of missing values or
small ranges (e.g. one or two values)
- Implemented timezone support, based on localized yes/no the dates will
be translated before rendering
- Added support for empty dates, instead of rendering separate points
for each empty date it will now be plotted in a single '(undefined)'
column

- Fixed the highchart implementation, still extremely unstable but has a
much better change of rendering now

Feature
- Added the 'stacked bar' option
- New Line Graph option to hide the circels around all datapoints in a
line graph
- New option to group dates by week