removed DialogToolsActivity
refactor: remove comments, extract methods
deleted unused member variables, refactored some names
Merge pull request #79 from Catrobat/Refactor_Remove_Activities

Refactor remove activities
refactored by: @galstc05
acceptance by: @mgerald
successful jenkins run: http://catrobatgw.ist.tugraz.at:8080/job/Paintroid-custom-branch-test/366/