Revert "Merge pull request #645 from realm/kg-core-0.87.0"

This reverts commit 44f4092b7dc39c7989399fb412cd9c8abca940f2, reversing
changes made to 68fbf8f3787999e461e68c534bc79dff143c06f7.

Conflicts:
	changelog.txt
Merge pull request #661 from realm/ez-rollback-core

Revert core to 0.86