* fix failure in TestProposerFrequency
* Add test to check priority order after updates
* Changed applyRemovals() and removed Remove()
Changed applyRemovals() similar to applyUpdates()
Removed function Remove()
Updated comments
* review comments
* simplify applyRemovals and add more comments
* small correction in comment
* Fix check in test
* Fix priority check for centering, address review comments
* fix assert for priority centering
* review comments
* review comments
* cleanup and review comments
added upper limit check for validator voting power
moved check for empty validator set earlier
moved panic on potential negative set length in verifyRemovals
added more tests
* review comments