[common_test] Extend timers for slave nodes in ct_cover_SUITE

Also, rename some nodes to avoid node name clash between test cases,
and ensure proper cleanup of nodes.
Remove obsolete common_test note regarding source paths
Add ct_slave:start(Node, Opts) to start a node on the local host

This is convenient when starting nodes locally since there's otherwise
no trivial way to specify the local hostname.
Minor edoc fix

edoc inserted a type spec into the signature ("Options :: Opts") when
@spec and code used different variable names.
Simplify doc of error return

As {error, Reason, NodeName} together with a Reason production.
Returning '/' when given as parameter to get_testdir
Merge branch 'siri/cuddle-with-tests' into maint

* siri/cuddle-with-tests:
  [sasl] Fix tests that compare execution time
  [jinterface] Kill process between tests to avoid consequential error
  [jinterface] Make tests handle space in path on windows
  [common_test] Extend timers for slave nodes in ct_cover_SUITE
  [test_server] Clean up unused code in test_server_SUITE
  [reltool] Increase timetrap timeout for reltool_server_SUTIE to 10 minutes
  [test_server] Fix encoding of HTML file references to work on windows
  [test_server] Use simpler tc name in unicode test to make it work on windows
Merge branch 'anders/common_test/slave_start/OTP-10920' into maint

* anders/common_test/slave_start/OTP-10920:
  Simplify doc of error return
  Minor edoc fix
  Add ct_slave:start(Node, Opts) to start a node on the local host
Merge branch 'fredrik/ct/get_testdir_restrictions' into maint

* fredrik/ct/get_testdir_restrictions:
  Returning '/' when given as parameter to get_testdir
[common_test] Add -force_stop skip_rest option when repeating tests

To allow a repeated test to finish immediatly, 'skip_rest' option can
now be used in combination with 'force_stop'. If this option is used,
only the current testcase will be completed after timeout is reached
when repeating with 'duration' or 'until'.
[common_test] Add support for testing repeated testruns

ct_test_support which is used in common_test's own tests did not
support testruns with -repeat, -duration or -until options. This is
now added.
Added testcases for ct_telnet and opportunity to connect to telnet without user and password.
Added option wait_for_linebreak - so that expect does not need \n to match
[common_test] Add tests for repeated testruns

ct_repeate_testrun_SUITE is added, which tests the following options
to ct_run:

-repeat N
-duration [-force_stop [skip_rest]]
-until [-force_stop [skip_rest]]
[common_test] Document '-force_stop skip_rest' option to ct_run
Merge branch 'siri/common_test/force_stop-skip_rest/OTP-10856' into maint

* siri/common_test/force_stop-skip_rest/OTP-10856:
  [common_test] Document '-force_stop skip_rest' option to ct_run
  [common_test] Add tests for repeated testruns
  [common_test] Add support for testing repeated testruns
  [common_test] Add -force_stop skip_rest option when repeating tests
Remove unused Postscript files
[common_test] Send unexpected logging to test_server's unexpected_io.log

If it could not be decided which test case a certain log printout
belonged to, the common test framework log was earlier used. Such
printouts are now instead sent to unexpected_io.log in test_server so
that there is only one place to look for "missing" printouts.
[common_test] Add test for unexpected I/O
Merge branch 'fredrik/ct/telnet_wo_line_breaks/OTP-10085' into maint