In order to test the REPL in isolation, we would have to mock out the
parser and interpreter. This is possible, but too much work for the
benefit (at least for now).
* tests/repl.scm: Deleted.
* Makefile.am: Remove it.
* geesh/built-ins/echo.scm: New file.
* geesh/built-ins.scm: New file.
* Makefile.scm: Add them.
* geesh/shell.scm (exec-let): Include built-ins in command search.
* tests/shell.scm: Add a test for this.
* geesh/parser.scm: New file.
* tests/parser.scm: New file.
* Makefile.am: Add them.
* .dir-locals.el: New file. Include indenting rules for Shell AST
forms and 'call-with-backquoted-input-port'.
Timothy Sample