Handle special characters in test case titles correctly.

Handle special characters in test case titles correctly.
* lib/autotest/general.m4 (AT_INIT): M4-quote and AS_ESCAPE AT_help_all
properly.
(AT_SETUP): M4-quote and AS_ESCAPE the title properly everywhere.
* tests/autotest.at (AT_CHECK_AT_TITLE): Add EXPANDED-TITLE-TO-TEST
argument.  Extend to check titles printed by ./micro-suite and
./micro-suite -l and the title in micro-suite.log.
(Backquote in a test title,
Single-quote in a test title,
Double-quote in a test title): Don't expect failure anymore.
(Backslash in a test title): Put a non-whitespace character after the
backslash so that Bourne shells might actually see it as an escape
sequence.
(Brackets in a test title,
Pound in a test title,
Comma in a test title,
Quoted Macro in a test title,
Macro in a test title,
Macro with single-quote in a test title): New tests.
(Macro with backquote in a test title,
Macro with double-quote in a test title,
Macro with backslash in a test title): New tests expected to fail.
* tests/torture.at (#define header templates): M4-quote this title in
AT_SETUP call so that no M4 code is commented inadvertently somewhere.
The visible effect was a stray [] in the testsuite output.