assertions 0.2.0

• Improved factor support for assert_includes() and assert_excludes()

• Added assert_connection()

• Added assert_set_equal()

• Added assert_one_of()

• Added assert_scalar()

• Added missing assert_less_than() assertions.

• Added assert_null() and assert_non_null()

• Added assert_length()

• Improved error messages when assert_create() arguments are inappropriate