Changed structure of JFM.

Changed structure of JFM.
- Proportional glyph width is now supported by width = 'prop'.
- Fixed the alignment of glyphs (e.g., U+201C).

	modified:   doc/s1sty.tex
	modified:   doc/sample1.pdf
	modified:   doc/sample1.tex
	modified:   src/jfm-mono.lua
	modified:   src/jfm-ujis.lua
	modified:   src/luatexja-core.lua
	modified:   src/luatexja-core.sty
	modified:   src/luatexja-jfont.lua
	modified:   test/jfm-bad.lua
	modified:   test/jfm-hang.lua
	modified:   test/test04-jfm.pdf
	modified:   test/test04-jfm.tex