0.9.0

A happy new year!!

• Add issue support by #{number} argument. For example, -r rhysd/git-brws '#8' opens this issue. This is useful when you see issue number in source file and want to open it directly.
• Fix path separator is wrong on Windows when specifying file path in repository
• Add manpage git-brws.1 for supporting git brws --help and man git-brws
• Add Homebrew formula. This is recommended way for installation on macOS since it automatically setup git-brws.1 and is easy to update.
• Improve check when a directory is specified with line number
• Refactor remaining old error handlings