fixed: Dcc32Task: .aliases, .namespaces, etc are private

Theese properties must be public to allow to redefine them externally.
fixed: test/test-delphi.rb failure
improve: test: test-delphi-android.rb: tests libs usage
fixed: cannot compile for Win32 after compiling for Android

As far as inherited class variables are common for all classes (ancestor
and successors) we need to reinitialize it every use (task execute).
fixed: Rake::GitChangelog: changelog is not generated when :since is not set
improve: Rake::GitChangelog: add :format option
improved: added Rake.set_env_to_vars method

This added method takes environment variables by a given list and adds
them to a variables list.