Major fix for measuring the peak radii

[jmdkastro]

derivefunc.pro:

• added surfcontrast floor of unity in f_zeta (does not make sense otherwise)
• changed zeta expression for constant-surface density discs
• changed zeta expression for two-dimensional Gaussians

derivephys.pro:

• changed f_createpdf to avoid uncommon issues for zero errors
• added new variables to the covariance/correlation matrix calculation
• included new arguments to derivephys function (surfglobal[s,g])
• incorporated new treatment of surface density contrasts as a function of {tgas,tover,tstar}
• updated mdotsf and mdotfb arguments
• included new derived quantities surfglobal[s,g] and surfcontrast[s,g]
• updated derivephys function output

fitKL14.pro:

• updated model expressions in f_fluxratio[star,gas]
• removed f_writebeta[star,gas] and added more general f_writetab
• updated surfcontrast[s,g] for every lambda during fitting process by interpolation
• obtain best-fitting surfcontrast[s,g], i.e. surf[s,g]_best
• updated all model (f_fluxratio[star,gas]) function calls to depend on surf[s,g]_best
• when varying lambda, also vary surfcontrast[s,g]
• added new output plots of surfcontrast[s,g] as a function of aperture size
• added new output tables for surfcontrast[s,g] as a function of aperture size
• updated fitKL14 function output

kl14.pro:

• moved up fitKL14 in the compilation order

tuningfork.pro:

• added separate calculations of geometric lambda_map as lambdamap[star,gas]
• made inter-peak distances double precision
• minimum flux levels set to tiny rather than zero
• simplified the gas-to-stellar flux ratio calculation used when ordering peaks by age
• introduced new surfglobal[s,g]: flux density contrast at aperture size relative to entire map
• made surfcontrast[s,g] depend on aperture size (i.e. peak flux/flux at size L) to enable fixing to lambda during fit
• updated fitKL14 arguments
• obtain best-fitting surfcontrast[s,g]
• updated blending check by using f_zeta
• updated derivephys arguments
• added surfglobal[star,gas] and surfcon[star,gas] to output
• reordered output