Implement decompression in lzmajs binary.
Move lib/encoder.js to lib/LZMA/Encoder.js.
Freeze objects in RangeCoder to make lookup of static methods faster.
Freeze objects in LZ to make lookup of static methods faster.
Refactor LZMA.Encoder to use same coding style as rest of code.

Reverted some 'improvements' to make this code match the Java upstream
more closely as well.  Correctness is more important than improvements
at this point.  (Once the code is working and we have test cases, we
might think about 'improving' the code further.)