Preparations for regexes on keys.
More Preparations: regexes on keys in principle partly implemented, but way too slow.
Regexes on keys: intermediate commit.
Avoid negation on key regular expressions.
Refactoring.
Further refactoring.
minor english fixes
Merge pull request #127 from harry-wood/patch-1

minor english fixes
Regexes on keys: implemented as filter for current data.
Refactoring.
Regex for keys: further refactoring, new functionality prepared.
Regex for keys: bugfix.
Merge remote-tracking branch 'upstream/master' into test751
Merge remote-tracking branch 'upstream/regex_on_keys' into test751