* lib.scm (exception:missing-expression): New.

	* lib.scm (exception:missing-expression): New.

	* tests/dynamic-scope.test, tests/eval.test,
	tests/r5rs_pitfall.test, tests/srfi-17.test, tests/syncase.test:
	Wrap tests in module (test-suite test-<file-name without .test>),
	following a practice that was used on a couple of files already.

	* tests/dynamic-scope.test (exception:duplicate-binding,
	exception:bad-binding): New.

	* tests/dynamic-scope.test, tests/srfi-17.test, tests/syntax.test:
	Execute syntactically wrong tests using eval.  With the upcoming
	new memoizer this is necessary in order to postpone the syntax
	check to the actual evaluation of the syntactically wrong form.

	* tests/syntax.test: Added some test cases and modified one test
	case.