Refactor interactive marking to period marking

Breaking changes:

Interactive marking now is called 'period' marking and structure of marking has become more nested:

   markedDates={
    {'2012-05-20': {periods: [{textColor: 'green'}]},
     '2012-05-22': {periods: [{startingDay: true, color: 'green'}]},
     '2012-05-23': {periods: [{endingDay: true, color: 'green', textColor: 'gray'}]},
     '2012-05-04': {disabled: true, periods: [{startingDay: true, color: 'green'}, {endingDay: true, color: 'green'}]}
    }}

v1.6.0

Migrate CalendarList from ListView to FlatList

v1.4.0

• Breaking change: removed arbitrary 12pt padding in agenda items. Add 12pt to your top margins of your rendered items to fix it.

v1.2.18

• added dateString prop to date object
• refactored basic marking type api

v1.2.17

• Add onDayChange prop to Agenda #31

• Added compatibility for react-native-web #2

• Add possibility to provide custom arrow components #28

• Fix agenda header day alignment #22

v1.2.15

• Fix agenda background
• Fix RN43 bug when press on number inside text

v1.2.13

• Add maxDate parameter (@nulleof #13)
• Add firstDay parameter (@nulleof #13)
• Fix for agenda scrolling #15
• Example improvements

v1.2.12

• Add a way to change color of day text when markingType=interactive

v1.2.11

• Add i18n support

Initial release

v1.2.10

1.2.10