`for-each' and `map' implementations do not operate on lists and vectors
interchangeably.
* module/rnrs/base.scm (vector-for-each, vector-map): New functions.
* test-suite/Makefile.am: Add test-suite/tests/r6rs-base.test to SCM_TESTS.
* test-suite/tests/r6rs-base.test: New file.