Add encoding-core module

[05nelsonm]

Add a base module (i.e. encoding-core) to:

• Move all common code to it
• Have common extension functions that utilize the Encoder/Decoder abstraction
  • So a new encoder (not implemented by this library) can be utilized if library consumer creates it.
  • Optimization, because right now there is a lot of unnecessary array creation. Would be great if the
    extension functions for the type (String, CharArray, ByteArray) were able to instantiate those types
    off the bat and then input things as decoding/encoding occurs by converting the returned Byte.
• Enable ability to have Encoder and Decoder classes which can be passed around
• Enable ability to stream bytes/chars in or out, and receive encoded/decoded bytes on the other end
• Encoder/Decoder configurations
• Give people the ability to easily create their own Encoder/Decoders