Add some unit tests.

* tests/session.scm, tests/auth.scm: New files.
* srfi/srfi-64.upstream.scm, srfi/srfi-64.scm: New files.
* Makefile.am (SCM_TESTS): New variable.
  (TESTS): Likewise.
  (TEST_EXTENSIONS): Likewise.
  (AM_TESTS_ENVIRONMENT): Likewise.
  (SCM_LOG_COMPILER): Likewise.
  (AM_SCM_LOG_FLAGS): Likewise.
  (tests): New target.
  (CLEANFILES): Add .log-files produced by tests.
Merge branch 'master' into tests-implementation

Conflicts:
	ChangeLog
tests/session.scm ("session?"): New test case.
tests/session.scm ("comparsion of sessions"): New TC.

* tests/session.scm ("comparsion of sessions"): Use one test case
  instead of two separated TCs (equal?/not equal? test).
tests/session.scm: Fix bug in TC.

* tests/session.scm ("session-set!, valid values"): Fix bug in TC: try
  all valid values for each option, not only the first one.
Add some unit tests for Guile-SSH server API.

* tests/server.scm: New file.
* tests/dsakey, tests/rsakey: : New files.
* Makefile.am (SCM_TESTS): Add `server.scm' test.
tests/.gitignore: New file.
Merge branch 'master' into tests-implementation

Conflicts:
	ChangeLog
tests/server.scm: Add new TCs.

* tests/server.scm ("server?", "comparison of servers"): New TCs.
tests/session.scm: Fix a typo in a TC name.

* tests/session.scm ("comparison of sessions"): Fix a typo in TC
  name.
Merge branch 'master' into tests-implementation
tests/server.scm: Add new TCs.

* tests/server.scm ("server-set!, invalid values", "make-server")
  ("server-listen"): New TCs.
tests/client-server.scm: New file.

* tests/client-server.scm: New file.
* Makefile.am (SCM_TESTS): Add `client-server.scm' test.
Merge branch 'master' into tests-implementation

Conflicts:
	ChangeLog
Merge branch 'master' into tests-implementation
tests/: Update TCs to use symbols for `log-verbosity' option.

* tests/client-server.scm ("connect"): Update test to use symbols
  for setting log levels.
* tests/server.scm ("server-set!, valid values"): Likewise.
  ("server-set!, invalid values"): Likewise.
  ("make-server"): Likewise.
  ("server-listen"): Likewise.
* tests/session.scm ("session-set!, valid values"): Likewise.
  ("session-set!, invalid values"): Update `log-verbosity' data set
  for the test.
Merge branch 'master' into tests-implementation

Conflicts:
	ChangeLog
tests/server.scm: `server-set!', check `hostkey' option.

* tests/server.scm ("server-set!, valid values"): Check `hostkey'
  option.
  ("server-set!, invalid values"): Likewise.
Use the standard `check' target instead of `tests'.

* configure.ac (AM_INIT_AUTOMAKE): Add `color-tests' option.
* Makefile.am (TESTS): Fix a bug: use value of `SCM_TESTS'
  variable, not its name.
  (tests): Remove target.  Use `make check' instead.
  (CLEANFILES): Add auxiliary logs produced by tests.
tests/server.scm ("server-set!, invalid values"): Improve TC.

* tests/server.scm ("server-set!, invalid values"): Don't check
  `bindaddr' with garbage strings because errors will be caught only
  on the subsequent call to `server-listen'.  The same for `rsakey'
  and `dsakey' -- errors will be caught on `server-accept' call.