[engineering] calculator app for iPhone and iPad

Engineering Calculator is a calculator designed to be convenient and simple while including functions necessary for scientific calculations. It has a calculation function for standard engineering and a function to save past calculations. You can also decorate your own calculator theme, and make various settings related to calculations.

Features include:
* Save/load calculation results and formulas
* Convertible to degre/radian and multiple trigonometric functions
* Number of fixed point can be set
* Various operations essential for calculations such as fractions and algebra
* Decorate calculator theme with different colors