wfcinit in the presence of spurious wfc files + minor updates
Minor updates to documentation, tests, make.depend. Not-so-minor correction to wfcinit.f90: with the new XML file, the presence of a spurios old-style wavefunction file could break reading wavefunctions. It seems to work now also for restart. It relies on the correct value of the variable twfcollect written to the xml file: must be .false. for files saved during a run, .true. for files saved at the end of a run.