Chagne ENV['HONYOMI_DATABASE_DIR'] rule

ENV['HONYOMI_DATABASE_DIR'] = /path/to/dir
brefore: /path/to/dir/honyomi.db
after:     /path/to/dir/db/honyomi.db
Puts 'honyomi init' message
Puts error message when 'pdftotext' is not found
Implement 'honyomi edit --no-strip'