mev v.1.15

New:

• gev and gp distribution functions (d/p/q/r) introduced to remove dependency on evd package.
• Ramos and Ledford score test of independence

Fixes:

• taildep function now correctly check choice of estimators against list of methods
• Fix argument size in likmgp and clikmgp for the logistic model
• Correctly return a covariance matrix with NAs when the matrix is singular or xi=-1

Changes:

• taildep arguments leads to faster calculations with betacop option.
• Replace nloptr dependency by Rsolnp