fix CharacterStrategy: could not handle empty existing pseuodnyms table
prepare TestDataFixture for reuse with other input files
use proper Exceptions in TestDataFixture
unified rule validation in Analyzer and Anonymizer

previously only Analyzer called TransformationStrategy.isRuleValid
and only Anonymizer checked if the PseudonymizeStrategy prefix length is feasible
now both use a RuleValidator which uses isRuleValid and prefix length checking
has been moved to PseudonymizeStrategy
take all columns as PK if none is defined
move AnonymizerUtils.getColumnDatatypeDescription to ColumnDatatypeDescription

because it is merely another constructor really
only check length for SetDefaultStrategy if column type is characters
treat dependent fields as in a foreign key relationship for deletion

otherwise if a parent row was deleted but the relationship was not implemented
in the DBMS as a foreign key, child rows of this row would not be deleted as well
and become semantically dangling
add German step-by-step manual

also fixed the invocation lines in the README files
use java.sql.Types constants instead of the type names

prevents typos and subtle differences such as whether the type is called
CHAR or CHARACTER in a DBMS
replace printing on stderr with logging in PseudonymizeStrategy
one character map per rule instead of a global map in CharacterStrategy

prevents identification of original characters for an unrelated field
if on another field some characters could be derived
add test for randomness of CharacterStrategy map generation
fix: CharacterStrategy did not produce shuffled pseudonym maps

i. e. no actual pseudonymization was performed
because each char was mapped to itself

the error has gone unnoticed because the unit tests
use a predefined character mapping
add test for CharacterStrategy.transform
refactor TestDataFixture

TestDataFixture is now abstract (with the template methods being abstract).

StandardTestDataFixture is what TestDataFixture used to be: it uses the
common test data files test-h2-config.txt etc.

TestSpecificTestDataFixture was extracted from
ForeignKeyDeletionsByConfigRuleTest so it can be reused for other
test cases.
add test for composed key deletions

(currently it fails)