Plane geometry: Line passing through 2 points (lines1).
Description: Geometry in the plane program, that may be used to display information about lines
passing through 2 points. The program determines the line's equation (several forms) and also calculates values as the slope
and the angle of the line with the x-axis.
Improvements: Reducing the equation coefficients, perhaps using fractions instead of decimals.
Free Pascal features: Classic pascal (records, functions, procedures). Crt unit (catching keyboard