Add funct to remove small connected compononents
Add examples to docstring
Add tests for remove_small_connected_components
Modify example to use remove_small_connected_components
Improve docstring for remove_small_connected_components

- Explain behavior if input is of int type.
- Add `Raises` section for possible errors.
- Remove explicit numpy import from example.
Rename function to remove_small_objects
Add raise and labeled image tests
Fix missed rename in example
Change data type of index variables
Add specific error messages and exceptions
STY: Minor cleanup.
Improve performance and usage of data types of hough circle transformation
Remove unnecessary statement breaks
Change color of circles for better visibility
Merge pull request #446 from jni/morphology-functions

Morphology functions
Improve performance of normalization
Merge pull request #452 from stefanv/jni-morphology-functions

STY: Minor cleanup on small object removal.
Merge pull request #450 from ahojnnes/hough-circle

RF: Hough circle improvements.
DOC: Fix typo in remove_small_objects docstring.
Add release notes for version 0.8