Path separator should not be hardcoded on Qtopia Core

There should be a way to modify the path separator for Qtopia Core at compile time (ie: switching between \ and /). Although this is not generally a problem because this happens in platform specific code where were generally know the separator, adding this feature would make porting Qtopia Core to new platforms easier. One solution would be to add the following to qplatfromdefs.h:

#define QT_PATH_SEPERATOR_CHAR '/'
#define QT_PATH_SEPERATOR_STRING "/"

OR

#define QT_PATH_SEPERATOR_CHAR '
'
#define QT_PATH_SEPERATOR_STRING "
"

and use this instead of hard coding the slash.