UPNP fixes and optimization

1) optimization: _xxxChilds: slice whole items array BEFORE converting to output objects
2) fix with special chars in items title.
Some players stops after receiving some special chars.
Don't know which exactly char is wrong, replace all special chars to '-'
Merge pull request #460 from SeregaPru/develop

UPNP fixes and optimization
Restore 'Update from tags' link on albums