Generalized Lambert W function - premature commit

I did some work on merging the specfun generalized lambert code with my code--no particular problems doing that.
But I noticed:

With GCL (OK, I think)

  (%i73) generalized_lambert_w(-1,float(-1/%e)-0.0000000001);
  (%o73) -2.3316436928788765*10^-5*%i-0.99999999981878

With either SBCL or 64 bit CCL (not so good?)

 (%i17) generalized_lambert_w(-1,float(-1/%e)-0.0000000001);
 lambert-w-k did not converge

 (%i2) generalized_lambert_w(-1,float(-1/%e)+0.000001); /* only tested with CCL */
 lambert-w-k did not converge
 
OK:

(%i3) generalized_lambert_w(-1,float(-1/%e)+0.0001);  
(%o3)                         - 1.023499619082082


--Barton