Add the required resources (images, JS, CSS) for `docwriter'.
* docs/reference/.gitignore: Update to ignore `site' folder and other
files generated by docwriter.
* docs/reference/README: Add docwriter usage information and
troubleshooting tips.
* docs/reference/markdown: New directory to hold generated markdown
files and other resources.
correctly to generate the API reference in 'docs/reference'
* src/tools/docmaker/tohtml.py: update to output nicer fields lists
in the API reference
* src/base/ftobjs.c (FT_Load_Glyph): FT_LOAD_TARGET_LIGHT now
forces auto-hinting
* freetype/freetype.h: updating the documentation for
FT_LOAD_TARGET_XXX and FT_Render_Mode values