Log Message:
Changes 1.10.0:
* Documentation: Context::arc(): Correct the documentation, as in the C
  documentation.

Changes 1.9.8:
* Surface:
  - added create() for creating a sub-surface representing a rectangle on a
    target surface
  - PDF versioning API: get_versions(), restrict_to_version(),
    version_to_string()
  - add get_device()
  - add new surface type enum values
* Device
  - add acquire() and release() functions
  - Add Device::Lock convenience class
* Region
  - UNSTABLE API CHANGE: Fix do_union(), subtract(), intersect() to throw
    exceptions instead of returning error statuses to be consistent with the
    rest of the cairomm API
  - add xor() functions
  - add API for creating a region from a list of rectangles
  - implement copy()