Currently, only CPU time is supported.

Found with clang -Wstrict-bool.

  - Built generic interface for alternative script sources.
  - Implemented dict script location.
  NOTE: ManageSieve will not work with this yet, nor will sieve_before/sieve_after.

- Added sieve_global_extensions setting.

- Administrators now get properly notified about uncompiled global scripts and the inability of the sieve plugin to store global binaries.
- Improved binary load/save error handling and fixed a few smal bugs.
- Simplified ManageSieve error handling.

Made sure that scripts are only recompiled when the script file - or the symlink pointing to it - is strictly newer.

Fixed race condition occuring when multiple instances are saving the same binary (patch by Timo Sirainen).

Be explicit about signedness of data in binary code representation. Some architectures, like ARM, differ in this respect.