WGXP version that always overwrites native

Hi Andrej,

Not sure if this seems an issue to you too, but the benchmarks for WGXP appeared so amazing on modern browsers because it uses native XPath in browsers that have implemented this. It's still fast but about a factor 10 less so than it appeared in the benchmarks.

This is the change made to WGXP to always overwrite native: https://github.com/kirang20/wgxp-java-rosa/commit/9bdb72e56e69603088ba002e98336f449f80e4a6