- Now compiles regularly without --with-unfinished-features
- Still experimental though, so be careful.
- Changed command structure a bit, removing the useless -M option.

- Updated documentation.
- Made editheader extension disabled by default

lib-sieve: optimized compilation of tests that yield constant results (i.e. known at compile tme), such as true and false.
If the result of a test is known at compile time, it is optimized away. If an if-command depends on an entirely constant test, it is optimized away as well,
causing only the 'true' sub-block to be compiled.

ManageSieve: removed TODO status of adding ANONYMOUS SASL support, since the RFC specification no longer describes it.

Enforced ManageSieve protocol syntax better with some of the commands; some commands still allowed spurious extra arguments.

- Changed operand read functions to prove exec status return codes in stead of boolean.
- Restructured optional-operand, stringlist and string-match APIs to provide execution status (error code) upon failure.
- Corruption errors are only produced when the binary is actually corrupt. Normal failures should never cause a recompile attempt anymore.
- Simplified optional-operand API.
- Cleaned up test command implementations that use the string-match API.

- 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.