Analyzer: Catch exceptions from alien code.
Analyzers: Test exception handling
Printer: Add boundary test
Parser: Remove __init__ (unneeded)
Settings: Mark exceptions for translation

All exceptions should be translated since they may be put out as debug
messages at some point.
Settings: Allow custom keys

This may be used e.g. for comments or any other thing
that may be there twice with the same key.
SettingsTest: Test insertion with custom key
Settings: Allow iterating while ignoring defaults
SettingsTest: Test ignoring defaults
Settings: Add __contains__()
SettingsTest: Test __contains__()
i18n: Update POT
Correct 'a analyzer' to 'an analyzer'
Add ConfParser
ConfParser: Add stubs
ConfParser: Open file, add __parse_lines stub
ConfParser: Add export_to_settings()
ConfParser: Add get_section()
ConfParser: Instanciate LineParser on creation
Settings: Move class comment up