startDate should be always set before endDate

[xersiee]

When updating picker's value programatically, it sets endDate first and startDate after this (this is determined by the order of options in getOptions). However, when setting endDate, bootstrap-daterangepicker ensures that endDate > startDate and sets startDate value to endDate if not. This can cause incorrect behavior in the following scenario:

1. Create date range picker in single mode
2. Combine it with <input> that can be edited and used to update picker's state from the outside
3. Initialize picker with some date, lets say 2018-01-07
4. Change manually date in the input to 2018-01-01 (must be date before original date)

5. Open picker - picker shows range 2018-01-01 - 2018-01-07

6. Close and open again - show correctly single date: 2018-01-01

Quick workaround in my code was to call setState({ startDate: ...}) first and setState({ endDate: ...}) in the callback, but I believe it should be fixed in react-bootstrap-daterangepicker's code, so setting two values at once works correctly.

[skratchdot]

closing this due to inactivity. please re-open if this is still an issue in v6.0.0 or greater