Revert "Merge branch 'doc_update' of https://github.com/genome/breakdancer into doc_update"

This reverts commit cf0bd3ad045b9ffaabdbe6dba9ca9423549483c1, reversing
changes made to a2448d69eedae0f0689b6e93efadf18da42bacd6.
Revert "move to one overview page"

This reverts commit a2448d69eedae0f0689b6e93efadf18da42bacd6.
Revert "deduplicate install instructions"

This reverts commit 2586237095f21b17dbdeffca61dd754d6db7982c.