Only calls that require space allocation are to be changed.

perl -i -pe 's/unsigned int ([^,:;]+):1;/bool $1:1;/' **/*.[ch]

Also contains a few other small fixes by Timo.

Clang static analyzer is happy now.

Imap4flags: added support for obsolete imapflags extension for backwards compatibility with CMUSieve.

Exported variable string argument into the Sieve engine itself as 'catenated string' (for similar use in other extensions like the testsuite).

Added the concept of a script code header to list the extensions actually used by a script (was using all extensions listed in the binary).

Enforced limits on string length and handled the finite nature of integers for number parsing and the construction of the AST.