Dimsense

Features
- Added SelectKBest feature selection method
- Introducing PCAExtractor for feature extraction

Bug Fixes
- Fixed issue 123: Bug in AutoencoderExtractor output

Enhancements
- Improved documentation for FeatureSelector methods
- Enhanced performance of TFIDFExtractor

Features
- Added LatentDirichletAllocationExtractor for topic modeling

Deprecations
- Deprecated old FeatureSelector methods (use SelectKBest instead)

Breaking Changes
- Removed legacy support for Python 2.x
- Changed parameter naming convention in AutoencoderExtractor