Remove unnecessary encoding comments

Because default script encoding is Encoding::UTF-8 after v2.0 and our
requirements is Ruby >= 2.1.0.
http://www.ruby-doc.org/core-2.1.1/Encoding.html#class-Encoding-label-Script+encoding
Remove redundant if statement
Fix bug appending path name of last board to `selected`
Merge pull request #7 from yous/patch-develop

Progress