Maint: Add ronn dependency for building man pages

Add missing dependency so that the `rake gen_manpages` task works.
Maint: Update man pages

Updated the man pages via the `rake gen_manpages` task.
Merge pull request #1393 from joshcooper/maint/master/generate-manpages

Regenerate manpages
Revert "Maint: Add ronn dependency for building man pages"

This reverts commit 758d3a5b5e610e6bb668bae432acb400baf939fe.

Bundle install installs all gems, including those in the development
group. But the ronn gem requires the devkit on Windows. Since we are
planning on moving the man page generation as a packaging step, I'm
reverting this.