Smart Photographic Calculator

Apr 24, 2020

* 2D graph engine for expressions is improved.
* Plot graph for 2-variable and 3-variable implicit functions. Note that implicit function must be an equation, not assignment, i.e. x**2+y**2=4-z**2 is invalid while x**2+y**2==4-z**2 is OK;
* Change behavior of functions size, zeros and ones;
* Performance improvement;
* A number of bug fixes for Android N and above;