Fix building/running on linux

[sandsmark]

I don't have windows, so can't test if anything breaks there, but it should be fairly easy to make it work on both

[Tapsa]

Not sure why you replaced wxString with std::string, since wxString is used all over the place anyway.

[sandsmark]

there was a build error otherwise, wxString doesn't provide whatever LRU_SLP needs, and the wx documentation said it was preferred to use std::string internally, so I just changed it there to make it build.