many bugfixes: inline mode, multi-month display, range selection, highlights

[geonanorch]

As pre-discussed per email, this is a jumbo PR with several bug fixes, here the ones I remember:

• inline mode:
  • calendar was not styled correctly (cells not square)
  • CSS now supports multiple instances (required for inline mode)
• multi-month display:
  • display is fully responsive (width not capped)
  • all month tables have the same size
  • day names are attached to each month, no more hard-coding for 3 months
• range mode:
  • cross-month selection and even cross-page selection (prev/next) now works as expected
  • single selection works better after a range selection
  • begin and end of selection have specific rendering
  • could not select in previous months after selecting with a month
• highlights:
  • hover on highlights failed for colors in format #nnn (format #nnnnnn was ok)
  • better error handling of parsing errors and missing colors
  • highlights are no longer overridden by hidden state
  • multiple highlights with same legend/color are properly handled
• colors:
  • always using @green (instead of @color = red) for month tables
  • cosmetic adjustments for next/prev areas

I might have broken a few things on the way, though I tried not to.

[xevin]

Tabs and spaces confusion. Why so ugly?

[geonanorch]

because I use a different editor, and forgot to adapt to datepickk standard with my 2nd commit. Should now be fixed. If not, could you clarify the problem?

[crsten]

I'm just writing to inform you guys that i haven't found time to implement this PR yet.
Looking forward to do it, and i'm still uncertain when i will find time. Will keep you up to date

[geonanorch]

Thank you, keep-alive signal appreciated. And no worries, is a big PR + most of us have to earn a living next to maintaining Git repos ;-)
One remark to the list at the beginning of the thread: display of multiple months in modal mode still needs fixing, corrections were done for inline/embedded mode only.

[ashep]

@crsten still haven't time? Really need that fixes. Thank you.