==========================================================================
 The function [TRC,CFG] = LOADTRACEM(FIELD,TRC_REDUCTION,SRC_NR,
                                     TOOLTYPE) 
 loads traces from trace-files, created with the FDTD algorithm fwi.
 
 FIELD         = field that should be loaded ('-1'=all -> returns a
                 structure or single field components '1'=Er, '2'=Ez or
                 '3'=Hphi(NEEDED)
 TRC_REDUCTION = trace-length 'nt' (#samples) to load. If set to '-1',
                 everything is loaded.
                 CAUTION: if TOOLTYPE==4x, this denotes the iteration 
                 number (NEEDED)
 SRC_NR        = shot-number to load (NEEDED)
 TOOLTYPE      = if 1=cartesian modeling tool; 2=cylindrical modeling tool,
                 3=reflex-data and 4x=cart+wave forminversion, where x
                 stands for 0 (simulated-), 1 (perturbed-), 2 (residual-) and 
                 3 (observed-) traces. (NEEDED)
 ECHOTYPE      = either 1 (every comment is ploted or 0 to disable the
                 comments). (NOT NEEDED)
 
 The return parameters are: Trc containing the trace(s); and cfg containing
 the configuration parameters
 
 REMARK: Concerning the Waveform-Inversion - the residual traces after an
 Epsilon-Inversion are ALLWAYS scaled in order to get rid of the Sigma-
 effects! So if REAL residual traces are needed, compute them by simply
 subtracting the observed from the simulated traces!
 
 (c) Jacques Ernst                                               ETH Zurich
 ==========================================================================