1) annotatedcont.xsl, objcontent.xsl, proofs.xsl, rootcontent.xsl: added LETIN
2) content.xsl, mmlextension.xsl: added LETIN and body to Variable,
changed color into mathcolor
3) content_to_html.xsl, html_init.xsl, html_reals.xsl, html_set.xsl:
changed color into mathcolor
4) reals.xsl: power instead of root