Font family matching does not conform to the CSS Fonts 3 specification

[cbfiddle]

There are some problems with the resolution of font family names that cause existing SVG files to render improperly.

The CSS Fonts 3 specification says that font family names must be matched case-insensitively (section 5.1). It also requires several standard font family names to be recognized: serif, sans-serif, cursive, fantasy, and monospace. These are not exactly the same as the default Java font family names, esp. Sans Serif (which is the default value in Text.java).

[don-vip]

I fixed the Java mapping in #30

Fonts remain to be matched case-insensitively.