Fix unicode bug in argument handling
Fix unicode bug in argument handling

When constructing an array of c strings from the NSArray of arguments,
for strings with non-ascii characters `[argString length]` differs from
the byte count of `[argString fileSystemRepresentation]`, which caused
argument strings to be truncated. This changes it to use `strlen` on
the `fileSystemRepresentation` for size calculation.

sveinbjornt/STPrivilegedTask,sveinbjornt/STPrivilegedTask,sveinbjornt/STPrivilegedTask