defer to stdlib for path.get_home_dir() We have elaborate and fragile logic for determining home dir, and it is ultimately less reliable than the stdlib behavior used for `os.path.expanduser('~')`. This commit defers to that in all cases other than a bundled Python in py2exe/py2app environments. The one case where the default guess will *not* be correct, based on inline comments, is on WinHPC, where all paths must be UNC (`\\foo`), and thus HOMESHARE is the logical first choice. However, HOMESHARE is the wrong answer in approximately all other cases where it is defined, and the fix for WinHPC users is the trivial `HOME=%HOMESHARE%`. This removes the various tests of our Windows path resolution logic, which are no longer relevant. Further, $HOME is used by the stdlib as first priority on *all* platforms, so tests for this behavior are no longer posix-specific. closes gh-970 closes gh-747