testing: add a unit test for the multiple regex match exception

Signed-off-by: Peter Williams <pwil3058@gmail.com>
layout: move all the exception classes to be together at the front

Signed-off-by: Peter Williams <pwil3058@gmail.com>
testing: check for unique handles on non release builds

Signed-off-by: Peter Williams <pwil3058@gmail.com>
regex: provide templates for regex lexemes to make life easier.

Has the added advantage that we can make sure the regex is anchored at
the start of the string. Hide RegexLexeme to avoid problems.

Signed-off-by: Peter Williams <pwil3058@gmail.com>