Do not crash when only some inputs are available.
Distance matrix now includes items that are used for annotating clustering results
Data table: sort selection along with data.
Remove score columns when data is unset.
Fix removed signals and error messages.
Removed deprecated comments.
File widget reports errors
Data table widget is now larger by default.
Update stats when learners are added/removed.
Extract _update_header method.
download_data creates AND populates X and Y (ref. abeec80)
Merge pull request #164 from marinkaz/distances

Annotating clustering results with data items
Merge pull request #171 from markotoplak/datatablesize

Data table widget is now larger by default.
Merge pull request #170 from janezd/file-widget-errors

File widget reports errors
Merge pull request #169 from lanzagar/owtree

Fix removed signals and error messages.
Merge pull request #173 from lanzagar/scatterplot-sql

Remove duplicate sql data download.
Merge pull request #167 from markotoplak/datatablesort

Data table: sort selection along with data.
Merge pull request #162 from astaric/test-learner-with-incomplete-inputs

Do not crash when only some inputs are available.
Add error/warning/info bar to widgts