Do dep-loop checking before removing alias, otherwise some variables disappear !

And it is now done only by Lic2soc (L2lCheckLoops is not used anymore)

Also, during this change, I was bitten again by the « "__" versus "::" in ident
names » problem again.

The core of this problem is due to the fact that I use LicDump both for
(1) dealing with internal ident names
(2) generating lustre files

Because of (2), ident names may depend on the ec or the v4 option. hence, internal
names were sometimes translated with "__" instead of "::".

To (try to) fix that, I've added a boolean flag to all "to_string" functions that
states whether the function is used for internal purposes, or for generating lustre
files.

It was quite a boring change, that triggered other problems, that I've fixed
in this (too long) commit :
 - -esa should force -en, otherwise bad things happen (-esa is used for -ec anyway)
 - in -esa mode, #/nor inputs tuples of bool, not arrays
 - fix the list of predi op that returns a type different that its arg (SocPredef)