By re-implemen/organize JDK's charset implementation package
sun.nio.cs to achive the following goals

(1)decrease the size of the charsets.jar by 50% (from current 3.4M to below 1.7M).
(2)ease the maintenance cost (most charset implementation to be generated during
JDK build time from text based mapping tables)
(3)improve the performance (speed up the nio encoding/decoding performance)
(4)replace the current sun.io.* converters with an "adaptor" to re-direct the
sun.io encoding/decoding to nio.charset implementation t finally remove the
burden of maintain sun.io.