Factorized out the generation of returns with noreturn exits in
generate_return and generate_template_return methods.

Added parsing of noreturn attributes in various syntaxes
(C syntax, C++ syntax, GNU gcc syntax).

To do so safely, added a C lexer, and a quick-and-dirty parenthesis parser
(including brackets, braces and angle-brackets for C++).  Using the
scanned list of tokens, processing parenthesised source code is easier
and safer than with regular expressions.

Related to: #783 cmock of the wrong file is generated.

Added --recursive to submodules update.

Co-authored-by: Crt Mori <[email protected]>

- Introduced CMock_memset and CMock_memcpy
- Updated tests.