Setting version to 0.8.1:

This release has full support for indexes. Significant changes:

- change name to _label, HasLabel for indexes
- add raw query methods to untyped graph
- rename all index methods to find, reduce duplication
- add all index classes and helper methods in typed graph
- add creation of indexes to untyped graph schema

version.sbt

@@ -1 +1 @@
-version in ThisBuild := "0.9.0-SNAPSHOT"
+version in ThisBuild := "0.8.1"