- we simplified the parser return values

- now the display of parser and lexer debug information is controlled
from the command line (with the options -P and -L)
complete_rg: now the empty binders are not treated especially
top: we isolated a fragment of slow code (process_streaming) to be
investigated. It can be enabled with the -1 command line option)
Makefile: we now create the etc directory when it is missing