Almost functional handle_all.py

Still, this should be renamed and refactored later. But now I can use it to
catkinize manifest files.
Fix imports.
Collecting all fields from the manifest file works.
Create a function for each extraction from the manifest file.

This makes it easier to unittest the extraction. Also the
get_fields_from_manifest() method is really simple now.

The create_package_xml_str() method can be simplified as well.
Add commets
We don't handle metapackages and architecture indep. yet.

Set both to False for now.
The bugtracker_url is "" by default.
Add make_export_section()
Use the correct file path.
Improce the create_package_xml_str()

 - Correct the dependencies that are added
 - rm replace_parts and conflict_parts for now
nicer description tag.
unittest make_section and make_section_commented.
test_dependencies are commented out.
Introduce make_bugtracker_seciton...

and move make_*special*_section methods into on spot.
Simplify create_gackage_xml_str.
Formating, comments and TODOs
Move file related function to utils.py.
Draft of handle_make.

Is that really it?
Also backup manifest file.
handle_all also handles the makefile now.