Use a ThreadLocal<Codec> variable to contain charset codecs

[jrte]

Charset codecs are used throughout ribose code. Storing them in a ThreadLocal<Codec> on first use allows them to be accessed anywhere. IModel.close() implementations detach the ThreadLocal<Codec> instance from the calling thread. But threads that do not directly or indirectly (try-with-resources) call IModel.close()call the static IModel.detach() method to rid themselves of the thread local Codec instance.

[jrte]

Fix is implemented in commit f83daba. There are interface changes:

• IEffector
  • javadoc comment changes only
• IModel
  • add detach() method to clear ThreadLocal from calling thread
• IOutput
  • removed decoder() and encoder() methods (use Codec methods)
• IParameterizedEffector
  • remove decoder parameter from showParamterTokens()
• ITarget
  • formatting changes only
• IToken
  • getName(CharsetDecoder) replaced with asString()
• ITransducrtor
  • formatting changes only
• BaseEffector
  • remove decoder() and encoder() methods (use Codec methods)
  • remove decoder parameter from showParameterTokens()
• BaseParameterizedEffector
  • remove decoder parameter from showParameterTokens()
• Bytes
  • add public static final Bytes EMPTY = new Bytes(Bytes.EMPTY_BYTES)
  • remove decode() and encode() methods (use Codec methods)
  • replace toString(CharsetDecoder) with asString()

[jrte]

Fixed in 87f6054.