bump version to 0.4.2

bump version to 0.4.1

bump version to 0.4.0 and update Cargo.toml

bump version to 0.3.2

bump version to 0.3.1

Merge pull request iwburns#21 from iwburns/bump-to-v0.3.0

bump version to 0.3.0

Merge pull request iwburns#18 from iwburns/bump-version-0.2.0

bump version to 0.2.0

slab_tree v0.1.4

add documentation link and bump version

bump version