1.3 (2017-06-28) Teemu Rintala <teemu.rintala.a@gmail.com>
*Fixed minor bugs and performance issues
*New feature: odag

1.2 (2015-06-02) Teemu Rintala <teemu.rintala.a@gmail.com>
*Oapply to use aggregate instead of tapply for significant performance boost. 
*Bugfixes in Ovariable Ops methods.

1.1 (2014-09-01) Teemu Rintala <teemu.rintala.a@gmail.com>
*Updated with more features (odebug, Minimize, odirichlet, unkeep, dropall etc.)
*A number of bugfixes in the Ovariable evaluation recursion.

1.0 (2013-07-09) Teemu Rintala <teemu.rintala.a@gmail.com>
*Rearranged and documented for CRAN submission.