Issue 1058: added factory for labels
Refactor RescaleFeatures and fix PruneVarSubMean::cleanup RescaleFeatures should be used with init() in order to aquire the min and range values for each vector. PruneVarSubMean::cleanup() did not set initialized to false
Fixes for tapkee

- Proper ratio limits for landmark methods
- Fixed crasher in exact t-SNE
Merge pull request #1083 from gsomix/feature/issue1058

added factory for labels