xrv: Radial velocity package

• continpars: Edit continuum subtraction parameters
• filtpars: Edit the filter function parameters
• fxcor: Radial velocities via Fourier cross correlation
• keywpars: Translate the image header keywords used in RV package
• rvcorrect: Compute radial velocity corrections
• rvidlines: Measure radial velocities from spectral lines
• rvreidlines: Reidentify spectral lines and measure radial velocities