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
Added the latest mpk file
test
Bug fix for showing categories on x-axis 
Fix for showing week nr's according to the ISO standard. Removed some redundant localization functions
bug fix for sorting an enumeration in a bar chart
Fixed sort order when using multiple series  (previously sorted on first serie only)
Implemented sort order on enumeration name   (previously sorted on first serie enum name only)
Fixed usage of the Pie chart using associations, or enumerations as categories
Many structural improvements to the test project
Merge branch 'jaspervanderhoek-master'