WIP - row detail view - provide alternative calculation (#304)
WIP - row detail view - provide alternative calculation (#304)

* row detail view - provide alternative calculation
The function `calculateOutOfRangeViews()` is somehow complex and doesn't work correctly on my side, however a much simpler version always work for me and I'm providing it as an alternative calculation method that can be enabled by a new flag "useSimpleViewportCalc" (which is disabled by default to keep previous behavior).

* row detail, fix rendered count calculation

* row detail, switch to using RowId instead of RowIndex
- the RowIndex can be problematic when user does filtering, the rowIndex is then offset, while if we use the rowId (id of the row datacontext object) this is always valid for calculation

6pac/SlickGrid,6pac/SlickGrid