3D: Fixed bug with 0 values

Testing for a var returns false if x = 0
Changed to test if var is defined
Utils issue
Fixed issue causing markers to show even on dense line series, in spite of new logic in 4.x where it should depend on series density.
Added more date parsing logic to the data module. Now integrates with Date.js, and uses Date.parse. Tries to parse all dates, but falls back to categories if dates are not sorted (which may be a sign that parsing went wrong).
Fix for #3195 changed map axes.
Various fixes after running automated tests
Fixed #3334: Missing animations in 3d pies
3D influences non 3d chart pie charts: halo and border
Fixed #3274: IExx .blur() issue
Fixed #2909, a regression causing chart click event not to fire when zoom enabled on touch devices.
Speed optimization of Series.setData, related to #3260.
Fixed #3274: IExx.blur() issue

use fireEvent instead of calling directly
New demo of chart container click
Utils: Attempt at closing memory leak on bath compare
Simplified container click demo.
Modal sample minor fix
Various fixes after regression testing
Closes #3395: added buttonPosition to RangeSelector

//DOCS
buttonPosition -> x & y
correction for zoomText in previous commit
Closes #3397: footerFormat does not replace variables

Abstracted tooltipHeaderFormat to process footer or header (now called
tooltipFooterHeaderFormat)