Merge pull request #1 from chrox/master

update Makefile for build configuration
Merge pull request #2 from chrox/master

update k2pdfopt to version 1.66
Merge pull request #3 from chrox/master

update k2pdfopt to version 2.00
Merge pull request #4 from chrox/master

eliminate hyphens for non-CJK characters
fix several static variable declaration that prevent multithread rendering