Sms-toolkit

- *ADDED* Added truncate message method

- *ADDED* Added the vobject library (stripping it down to just the vcard class).

- *BUGFIX* Fix the correct encoding in py2 and py3 for unicode characters outside the BMP

- *BUGFIX* Fix `total_segment_length` calculation for UCS-2 encoding
- *BUGFIX* Calculate MMS properties similar to how UCS-2 encoding is calculated

- *ADDED* Add a "max_segment_size" field in the profile response.
- *BUGFIX* Fix the "message" in the segment body

- *BUGFIX*: Better handling of utf-8 encoded strings.