When loading a model in a different folder, the tool has to move to this
folder to find the ASN.1 files that are referenced without any path
information.
The tool used to return immediately to the folder where is was called
from. The problem is that subsequent model checks would fail because
they would not know the path of the asn1 files anymore.

Remove extra README

Small updates to README

Some errors were only reported on the screen by antlr, Now they are
caught by the tool

Antlr stops parsing after the rule is completed, meaning that there may
be some syntax erros that could not be unit tested
e.g. task x := 5;o
the "o" would not be detected as a syntax error if the "task" rule is
completely parsed. the EOF token should help, however it does not: when
using the parser in interactive mode it does complain, but not in
standard parsing..
The workaround is to check the index of a possible following token after
parsing the rule. If it is not none, it means that the buffer still
contains something, which therefore is a syntax error.

Python3's map function behaves differently from Python2 - it creates a
generator instead of actually executing the calls on the spot.
However it was wrong to use a map when nothing was returned and only
side effects were used.

standard SDL syntax. Also works with parameterless procedures

ASN.1 constants, when numerical, had to be replaced by their actual value in decision branches, instead of using the range of their type.

Fix

See merge request !8

Replace the unicode character with _0_
There should be no risk of conflict with a user identifier since SDL
identifiers cannot start with a number