[latexrefman] move fontenc package, expand Fonts

[Hefferon, Jim S.]

I followed Karl's suggestions, and added a few more points about the fontenc package (in particular that it allows you to enter more than one font encoding).  I removed the line for lmodern from the intial example.  But left a reference to it and cm-extra in the "blurry" paragraph.  

Added talk to the Fonts chapter.  In particular, put in stuff about the Font Catalogue, which is a great suggestion.  Also note that xelatex and lualatex can use system fonts.

Hoping to get to \DeclareTextCommand-type stuff next.

Jim

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