Fix crash due to race condition

Because the addition of a header view is synchronous, but view removal is done in View.post(), there can be a case when two adds happen in a row, and it can lead to a crash. Performing both operations in View.post() resolves the issue.

Migrate to AndroidX

1.1.0

Merge branch 'switch-to-jitpack'

Add notifyDataSetChanged & make updateSection handle section size updates

• Add notifyDataSetChanged method to BaseSectionAdapter
  Previosly, there was no correct way to notify about complete
  reset of data in adapter.

• Make SectionManager.updateSection handle section size updates
  Old implemenation of updateSection was expecting that section size
  remains the same. Now it handles such changes and updates
  sectionToPosSum properly.

Add GridLayoutManager support

1.0.2

Switch to jitpack publish configuration for 1.0.2

Set library minSdk to 16

1.0.1

Switch to jitpack publish configuration for 1.0.1

Initial version

1.0.0

Switch to jitpack publish configuration for 1.0.0