added RenderSpanElement property to Literal control
added RenderSpanElement property to Literal control

resolves #108

darilek/dotvvm,riganti/dotvvm,kiraacorsac/dotvvm,riganti/dotvvm,darilek/dotvvm,kiraacorsac/dotvvm,riganti/dotvvm,kiraacorsac/dotvvm,darilek/dotvvm,riganti/dotvvm