Add 'module test' command to trigger when called execution of a
ModulesTest procedure in target modulefile following same kind of
mechanism than 'module help'.
If ModulesTest procedure is missing from modulefile, a 'Unable to find
ModulesTest proc' message is displayed but no error code is set. If
ModulesTest procedure returns 1 (true), test is considered successful and
message 'Test result: PASS' is displayed. If ModulesTest returns no or
any other value, test is considered failed and message 'Test result:
FAIL' is displayed. In this case, module command exit in error.
Adapt bash and tcsh completion scripts for the new command. Describe new
command and new mode in docs.
Adapt existing non-regression tests and relative test modulefiles for
new command and new mode in 00-init, 50-cmds and 70-maint suites. Add
085-test tests in 70-maint to check coherent behavior of new command.
