#188 Outertext() function return html with different charset encoding in same call

[Slava]

A charset conversion (_charset!=_target_charset) not work always. Some nodes (or nodes attributes) can be converted, other - stay without conversations. There is two normal solutions to fix this issue:
1: Call convert_text() everywhere on output and back on input
2: Dont call convert_text() anywhere (and inside outertext() function too)

There is diff for PARTIALLY solution for that problem (for outertext() function).