Next to FlagEncoders for edge properties, TurnCostEncoders are now held
by the EncodingManager. A TurnCostEncoder encodes and decodes turn
restrictions/turn costs of several vehicle types into an integer flag,
like FlagEncoders do. For CAR, BIKE a DefaultTurnCostEncoder has been
declared, which stores turn restrictions only (yet). For FOOT a
NoTurnRestrictionEncoder has been defined, which encodes whether
restrictions nor costs. To define which TurnCostEncoders should be used,
the EncodingManager accepts a second list of turnCostEncoders, which can
be defined the same way as edgeFlagEncoders are defined. 

However, those TurnCostEncoders are not beeing used anywhere in the
code. This is just preparation for turn restriction support, which will
be introduces step by step.