V2.3: Bug fixedversion

V1.9, 2.0: Upgraded the build compiler

V1.7:

History lists remember the coordinates / modes

V1.5:

Minor changes in mode selection

V1.4:

Added the camera view as a background

V1.34:

-Set the max screen ratio for Galaxy S8

V1.33:

-Added Custom keyboard.

-Hide/show Menu bar

-Added Function list

V1.3:

-Added cylindrical z(r,t), cylindrical r(t,z), spherical r(t,p), and parametricx(u,v); y(u,v); z(u,v) surface 3D plots.