Updated docs and some default settings

Solves #59

* Updated default settings for g:LatexBox_cite_pattern to
  '\c\\\a*cite\a*\*\?\(\[[^\]]*\]\)\_\s*{'
  * This will work with more LaTeX packages, in particular with biblatex
* Updated default settings for g:LatexBox_ref_pattern
  '\C\\v\?\(eq\|page\|[cC]\)\?ref\*\?\_\s*{'
  * Added [cC] in order to match for cref and Cref commands
* Made some minor clean up in docs