API 650 Tank Design

Sep 29, 2015

-fix for summary print out error (free version only), where weight of roof/platform is reported as 1000x of input. Thanks to user feedback.

Added in app purchase for removing Ads, support for SI and Imperial units, designing the bottom annulus as maybe required, save and restore input, and export design result as text file.

updated to API650 12th edition (2013)