Generate better Harfbuzz type names

[jwharm]

HarfBuzz types are postfixed with _t in C, like hb_font_t. This leads to Java types like FontT. The trailing T is unnecessary and doesn't look very nice. With this change, the HarfBuzz types in Java will loose the trailing T so hb_font_t will generate a Java Font class. The change is not specific for HarfBuzz, but will apply to all type names ending with _t.