Log Message:
Update nkf (and p5-nkf) to 2.10.
(while here, added commented out LICENSE=zlib-liccense)

This release is maintainance release, mainly for bug fixes.
* Add install target to Makefile
* Let to recognize hankaku-kana in 8bit JIS
* Fixes perl module build
* Fixes no effect of -Z1, -Z2 and -Z0 option
* Fixes input specification for UTF-16 and UTF-32
* Fixes missing BOM output for UTF-32.
* Fixes miss guesses and output for 4bytes UTF-8