CharsetConverter: add UTF-8 <-> UTF-32 and UTF-32 <-> wide conversion functions
CharsetConverter: add convenient overloads to new conversion functions
Merge pull request #3317 from Karlson2k/charsetconverter_rework_02

CharsetСonverter rework - Part 2
[3D] add stereomode to streamdetails
[3D] expose stereomode to skins via ListItem.StereoscopicMode and ListItem.IsStereoscopic
[3D] add stereomode flags to Confluence