Log Message:
update to pydot-1.2.2

# `pydot` changelog

## 1.2.0 (2016-07-01)

- Python 3 compatibility
- bumped dependency to `pyparsing >= 2.1.4`
- tests running on Travis CI
- tests require `chardet`
- detect character encoding for most test files
  using the package `chardet`

API:

- on all operating systems, search GraphViz
  executables in environment `$PATH`,
  using `subprocess.Popen`.
  No paths hard-coded due to security and privacy issues.

- add option to pass GraphViz executable name
  or absolute path as `prog` to `pydot.Dot.write_*` methods.
  This provides an alternative to
  adding GraphViz to the `$PATH`.

- the functions:
    - `pydot.graph_from_dot_data`
    - `pydot.graph_from_dot_file`
    - `dot_parser.parse_dot_data`
  changed to always return a `list` of graphs,
  instead of behaving differently for singletons.

- require that the user explicitly give an encoding to
  the function `pydot.graph_from_dot_file`,
  with default encoding same as `io.open`.

- decode to unicode at program boundaries, and
  treat binary images as bytes,
  for more compatibility with python 3.
  Use `io.open`, instead of the built-in `open`.

- rm function `pydot.set_graphviz_executables`

- rm attribute `pydot.Dot.progs`

## 1.1.0 (2016-05-23)

- compatibility with `pyparsing >= 1.5.7`

API:

- `pydot.Graph.to_string`: hide `subgraph` keyword only if so requested
- produce `warnings.warn` if `pydot.dot_parser` fails to import,
  instead of `print`

## 1.0.29 (2016-05-16)

- Maintenance release that keeps the same API
- pin `pyparsing == 1.5.7`
- update version number in source code
- update `setup.py`