Changes to get jpexs building on Linux.

The classpath.split() argument was being interpreted as a regex on my system, so it was splitting between every character, rather than just at the `|`s, and thus the build was failing. This seems to be the case because classpath is a *Java* string rather than a *JavaScript* string, and thus with [different semantics](http://stackoverflow.com/questions/20244995/strange-result-of-javascript-split-in-ant) of it's `.split()` method.

Also change to using forward slashes rather than backslashes for the tests, these should work on both Linux and Windows.