Feature: Add titleProvider parameter to views

[pollputty]

Hello,

The purpose of this PR is to add the ability to customize the string displayed in the header of DayView/WeekView/MonthView. This is especially useful when the client application wants to add localization to the way the dates are displayed without having to implement again all the actions supported by the default header components (like jumping to another date).

I only noticed once I made these changes that there is already a PR with the same goal ( #36 ). There are two main differences between this PR and #36:

• this PR also supports WeekView and MonthView;
• the signature of the parameter matches the number of dates available to the view (one for day and month, two for week), which seems like a more natural API. The components' states are responsible for wrapping it in an actual StringProvider.

Have a nice day!

[ParthBaraiya]

Hi @pollputty , Please rebase this brand on develop or master.

[ParthBaraiya]

Changes are included in PR #107 .