[threeten-dev] tzdb compiler cleanup

[Xueming Shen]

Some cleanup on tzdb compiler to prepare for a public tool.

-removed the n-version supporting code, which, as we agreed, the JDK
  tool will never generates. This brings us much simple code.
-replaced the StringTokenizer with Scanner. We definitely should avoid
  using a "semi-deprecated" class in new code
-updated to use nio.file for those "File" operation, for no obvious reason:-)

http://cr.openjdk.java.net/~sherman/jdk8_threeten/tzcompiler2

-Sherman