In well-described fonts, this enables multi-line text (e.g. in manuals) to be
more readable.
The term "height" is also replaced with "line spacing" in Font's code.
This reduces the number of required preprocessor directives, leading to
more readable code and more code being examined by the compiler (useful
to spot problems). Since the method is inlined, the compiler should be
able to eliminate the same amount of code that the preprocessor would,
only at a later stage of the compilation.
This fixes a bug with the captured background being wrong when using
double buffering. Also it ensures that for example the clock in the
status bar is updated when the context menu is open.
