Decay fix

This fixes a fairly major issue that went unrecognized with ENSDF parsing where some nuclides were being passed over.  This was discovered because At-219 was being skipped, which is a key member of the U-235 decay chain.  Even though I wrote this code originally, I don't fully blame myself, because the ENSDF language is the so stupid here.  When they have approximate data for a reaction (I think) rather than saying

`%<rx>=<value>`

like they for most reactions, they instead use the syntax

`%<rx> AP <value>`

Yes, there are spaces on the sides of the `AP` and not on the sides of the `=`.  Why you would override the equals sign, I'll never know.  Someone please save the world already...

![fail_cat_jenga](https://f.cloud.github.com/assets/320553/1443032/805e57d0-41d2-11e3-8b19-c67b1d3efb85.jpg)

This also represents an aborted attempt to fix up the decay part of transmute by setting the destruction rate to zero, using @gonuke's suggestion. There were some recursion issues I couldn't debug in time so I reverted.