changed PPR default installation name #2

starting Magik images aborts, when PPR install path name includes spaces

Reason is, that the used Smallworld image launcher *gis.exe* has problems,
when his command line argument *-run_script* is used with a path, which
includes spaces. Using quote sign ("E:\T T\t.script") does not help.

As WorkAround, the used PPR default installation name is changed from
*Portable Python Robot VERSION* to *Portable-Python-Robot-VERSION*. Also a
hint *Known Problem* is added inside the README, that PPR should be
installed in a path without spaces.