removing NO_USE_SETFILENAME and USE_UP_NODE_FOR_ELEMENT_UP

[Patrice Dumas]

Hello,

I would like to remove two customization options:

NO_USE_SETFILENAME
If set, do not use @setfilename to set the document name; instead, base the
output document name only on the input file name. The default is false.

USE_UP_NODE_FOR_ELEMENT_UP
Fill in up sectioning direction with node direction when there is no sectioning
up direction. In practice this can only happen when there is no @top section.
Not set by default.


These customization options are set when TEXI2HTML is set.  I think that
they were added for the purpose of compatibility with texi2html.
However, beside strict compatibility with texi2html (which was an
important feature to have in 2010, but is not relevant today), I do not
think that these customizations options are useful, even for users who
would want compatibility with texi2html, as there are many ways to set
setfilename and the USE_UP_NODE_FOR_ELEMENT_UP option is not clearly
useful (or even confusing).

Unless there is some feedback, I will remove those variables soon.

-- 
Pat