Some code examples still use "t."

libtaxii used to store constants in libtaxii, which were often used as such:

``` python
import libtaxii as t
binding = t.CB_STIX_XML_111
```

However, these constants are now in libtaxii.constants, and this is the correct idiom:

``` python
from libtaxii.constants import *
binding = CB_STIX_XML_111
```

The examples need to be combed through and updated to reflect the new idiom.
