* module/system/base/compile.scm (<cenv>): No more cenv, it was a useless
data structure.
* module/system/repl/command.scm (*command-table*): Remove `use', it's
the same as `import'. Otherwise in this file, adapt to the repl having
direct pointers to the vm and the language, and to the module being in
the current-module fluid.
* module/system/repl/repl.scm (prompting-meta-read):
* module/system/repl/common.scm (<repl>): The repl now has a direct
pointer to the vm and language. Adapt accordingly.
* module/system/repl/command.scm (system): Declare exports in the module
declaration.
* module/system/repl/repl.scm (start-repl): If the evaluation returns
multiple values, print them separately.
* module/system/base/syntax.scm (system): Don't re-export receive or
and-let*; modules should explicitly import these if they want to. Don't
export an empty stack-catch definition!
* module/system/repl/command.scm (system): Pull in and-let*.
* module/system/vm/disasm.scm (system): Don't import and-let*.
