correct argument and variable names
since most options are optional show required text
deprecate --data and --issue-body and make commits default
rename --tagname to --tag-name
remove duplicate issue body option
support for --no-merges, --only-merges, --only-pulls, --use-commit-body
update script name in usage text
update README.md
Merge pull request #14 from lalitkapoor/14-flags-to-improve-what-merge-items-to-into-the-changelog

flags to improve what merge items to into the changelog