Optimized number of UI calls
Added testsuite for SlideShow changes
Optimized UI refresh - current package progress
Added test for SubProgress method
Using constant UI ID directly from SlideShow
Renamed test file
Changes as described in review

- RSpec: stub -> allow
- better sanitizing of value(s) and label(s)
- reusing internal methods instead of calling UI directly
- a few minor other changes
Fixing description
Merge pull request #249 from kobliha/SlideShow

Optimized number of UI calls in SlideShow