Removed several properties and methods in order to isolate converter
logic inside converter class
Removed several properties from input unit in order to isolate input
unit logic inside
Fixed issue with incorrect computation of the initial buffer size of the
converter unit
Added method that can be used to set output unit sample rate, leveraged
this api in converter unit
Minor refactoring for output unit
Added outputFormat property for engine object. This property can be used
to enforce 24bit PCM output format. fixes #11