Removes legacy/unused code
Adds a temporary, public lookup_face() method to the texture cache

This is to allow apps to reuse an FT_Face created by the texture cache.
Populates the layout left and top of the glyph in a tex cache surface
Breaks and organize lookup_font_glyph() code in tex cache
Adds a new draw_char_unicode() method to GlrLayer
Adds zoom-in/out to the examples using ctrl+/-
Adds new examples text-layout to showcase text drawing using harfbuzz
Adds new arabic and chinese font files