added function for multiple wavelengths

updated set_wavelengths function

adds list PID_CONSTANTS

added 413nm laser to connection options

imporves the delay aspect of the PID

decreased the size of the dead zone

The program now runs once ever second

protects against occastional connection timeouts

fixed the calls for the get_wavelength function

fixed type

imporved get wavelength function

adds protection for multi-mode measurements

removed plotting elements

replaced if statements with a clamp function

fixed change limit