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.
Settings: Allow iterating while ignoring defaults
Settings: Add __contains__()
SettingsTest: Test insertion with custom key
SettingsTest: Test __contains__()
SettingsTest: Test ignoring defaults
i18n: Update POT
Correct 'a analyzer' to 'an analyzer'
Merge pull request #59 from sils1297/wip/settings

Refine settings