feat(datepicker): full six-week calendar

[Foxandxss]

This was another of the ideas discussed at #1599.

By @bekos suggestion, I created this with a new option.

For me it makes more sense to have this behavior by default, that is what other calendars usually does and I prefer this than a jumpy calendar. Anyway I made a fullCalendar option to disable it if you want the old jumpy behavior.

[bekos]

@Foxandxss Nice work. I changed my mind, do this the default behavior with no option by the user :-)
Except jquery UI I couldn't found another example with variable number of rows.

[Foxandxss]

I created the no-option version and I said, well, I will add the option :P. Sure, I will modify it when I finish some work I have first 👍

[Foxandxss]

Well, this is done waiting for the accessibility merge.

[bekos]

There is a problem with Jenkins, it doesn't fire when I push a branch. I cannot merge without a green light from there.

[Foxandxss]

Jenkins is a lazy guy, it works some days and other days it doesn't :P

[bekos]

I think our guy too lazy lately!

[bekos]

@pkozlowski-opensource Any help on the jenkins issue?

[Foxandxss]

I updated this because I realized I left an unused function when I removed some code.

Feels good when you delete code.

[Foxandxss]

Rebased.

[bekos]

@Foxandxss Landed as b0b1434!