for every boolean config value now values true, 1 and '1' are accepted as true, everything else (or missing) is false
reduce code duplication and simplify init of boolean values with new method mapToBoolean()
simplified to much by moving to much logic into the mapToBoolean() method; isset check back to consumer functions
added mapArrayKeyWithDefaults as Pablo suggested
added mapArrayKeyWithDefaults as Pablo suggested
refactored a bit config booleans
Merge branch 'upstream-master'