Utility: doc++
Utility: added Directory::write() convenience function.
Utility: test also that nothing is lost in Directory::read/write() after 0.
Containers: added Array[Reference]::data().

Sometimes you need to explicitly access the data and the following is
too inconvenient:

    Containers::ArrayReference<const char> a;
    const char* data = static_cast<const char*>(a);
Utility:: added Directory::{read,write}String() convenience overloads.

readString() is slightly slower than read() due to the additional copy,
but writeString() has equivalent performance.
Using Utility::Directory::{read,write}() where possible.

Much shorter code now, also shaved second or two off build time thanks
to removed <stream> includes (1:50 before, 1:48 now).