care: Escape all ' (single quote) characters from env. variable values.
Allow dynamically linked versions of CARE.

The new "raw" format was introduced, it is the default when CARE is
not built as a portable binary to force users to use `care -x` to
extract files.  Also, proot is not copied into the archive if CARE was
not built as a portable binary, instead the re-execute.sh script tries
to retrieve proot from $PATH or $PROOT.