Release 0.5.0

add Iterators, keys count

tag v0.4.0 PlayStore

v0.4.0 release Snippets app to playstore

[maven-release-plugin] copy for tag snappydb-parent-0.2.0

[maven-release-plugin] copy for tag snappydb-parent-0.1.1

[maven-release-plugin] copy for tag snappydb-parent-0.1.0

Update README.md

Update README.md