* include/Utils.h,
src/Utils.cc: added mount() and unmount()
* src/Win_GParted.cc,
src/jfs.cc,
src/xfs.cc: use Utils::mount and Utils::umount instead of wrapping
CLI tools.
* replaced the inline Utils functions with static functions.
This shaves a few kbytes (24 in fact) off the binary and is a bit
cleaner code-wise (imho).