Fix lseek and getdents

Wrong data types and casts led to wrong values on 64 bit machines
with high values filedescriptor positions.

Fixes DirConsistency and DirSeek test case
Add additional note that testcase might fail if
uclibc is compiled without symbolic printf support
Remove unused testing-dir
Merge pull request #69 from MartinNowack/fix_runtime_posix

Fix runtime posix