Some issues with SparForte and the language

[specing]

All issues based on 2eb28f7a4d6c8cf7157b2010078d3cf3c6774de0:

1. the rules around end loop;, end if;, end <name>;, ... could be made more lax such that end; would be enough.

2. Is there a way to read a number in arbitrary base? Specifically numerics.value does not understand 0x... notation.

3. Huh? Shouldn't it be an exception?

raise constraint_error with "String repr does not start with 0x";
      ^--------------^ constraint_error is a variable not an exception

4. How does one use rem and mod in scripts?

case 20 rem 16 is
     ^^ identifier expected, not a number
case n rem 16 is
       ^-^ is expected
=> ? 20 rem 16
 4

5. Command completion in shell mode is not working

6. When spar is restarted, command lines issued from previous sessions are not loaded.

7. neither start-up greeting Type "help" for help nor help print SparForte version.

8. pkg_cmdline.html: s := command_name - number of environment vars in documentation is wrong? (it does not make sense).