added tests for rmdir, mkdir, reading, writing and reading with offsets
added tests for rmdir, mkdir, reading, writing and reading with offsets

spthaolt/libsqlfs,guardianproject/libsqlfs,spthaolt/libsqlfs,spthaolt/libsqlfs,guardianproject/libsqlfs,spthaolt/libsqlfs,eighthave/libsqlfs,eighthave/libsqlfs,guardianproject/libsqlfs,guardianproject/libsqlfs,eighthave/libsqlfs,eighthave/libsqlfs,spthaolt/libsqlfs,guardianproject/libsqlfs,eighthave/libsqlfs