show does not work for LatexExpr

[novoselt]

For example
show(latex(x^2))
in SageNB results in typeset x^2, while cloud shows LaTeX code x^{2}. Same for manually constructed expressions like
show(LatexExpr("x^2"))

This is a problem for functions that return LatexExpr with the idea of showing their output typeset when typeset_mode(True), e.g. http://trac.sagemath.org/ticket/18852

[williamstein]

One approach could be to handle a case involving show and types in sage_salvus.py (?)