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

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.

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.