move to ctex from bare CJK/xeCJK

* base on ctexbook. Use UTF8 option. Thus can compile with pdflatex.
  (Note that GBK support is to be verified.)
* fontname.def use standard xeCJK syntax. Note it will be used
  only when nofonts option is specified and when xelatex is used.
thuthesis.dtx: fix title font with pdflatex

* ctex use YouYuan as the Chinese sans-serif font, which is not desired
  in the template.
main.tex: add explanation for *fonts options
thuthesis.dtx: walkaround no footnote mark issue
fix compilation of shuji and thuthesis doc
shuji.tex: adjust raisebox height for eng words
drop GBK encoding support
Makefile: compiler default to xelatex, add pdflatex support
fix non bachelor's auth page margin (issue40)
thuthesis.dtx: \zijuabs converted to ctex's \ziju
use ctex's Chinese font family macros

We now use ctex's Chinese font family macros instead of shorthand ones
(\fangsong vs \fs). This is to provide a simple and standard font
switching interface.
thuthesis.dtx: update doc about font conf
thuthesis.dtx: update doc on relevant changes
zhfonts.py: fix fc-list cmd, fontname.def output
thuthesis.dtx: remove excess spaces in CJK date
not publicize adobefonts; fontname.def use 6 fonts
chap01.tex: check existence of \lishu, \youyuan; fix table pos
Merge pull request #44 from alick9188/ctex

Transition to ctex
subfig -> subcaption