Tool fixes to handle spaces in file paths

These changes collectively fix #655. Most of the changes add proper double-quoting to shell scripts so that they properly handle spaces in the path leading to the K installation directory. The `KRunner` tweaks handle the case of spaces in the path leading to the user's `*-kompiled` directory. For that we use backslash-escaping, a feature supported by Maude's `load` command.

Unfortunately, running `ant test` currently fails even for a pristine snapshot of the K master branch in directories with no spaces. Therefore, I can't definitively say that this fixes all spaces-in-paths bugs while introducing no new regressions. I can say that my changes are both necessary and sufficient to make the first several tutorial steps work when there are spaces in paths. Those steps involve using `kompile`, `krun`, and `kast`. I have not tried other K tools suck as `kagreg`, `kpp`, or `ktest`, even though I have made the obvious fixes to those shell scripts too.