since it is not interpreted as infinite by CVC4

As a side effect, this puts symbolic links back inside the archive. They
had been lost since 0.82 and prevented the use of a local installation.

It is now done by a different mechanism than parsing of time:
timeregexp is not any more used for parsing of steps, stepsregexp is
used instead.

- Switch from AUFNIRA to AUFBVNIRA logic in cvc4_bare

This commit also removes the laziness for accessing symbols, since they
are already in the scope at the time the plugin is loaded.

this allows to provide the time limit on the command of CVC4, and perhaps Z3 later.

Conflicts:
	examples/bts/execute.mlw

(reported by mario.alvarez739@gmail.com)