Merge pull request #2534 from minrk/unicode-argv

cast argv to unicode before testing
Fix for compiling ttconv in extern directory
Merge pull request #2535 from ianthomas23/extern_directory_fix

Move external libraries to 'extern' directory - correction
add more spectrum functions and add new spectrum types to specgram in mlab.py, and clean up window and detrend functions in mlab.py
add mlab tests for new spectrum types, window and detrend functions, and greatly expand existing tests
add CleanupTestCase, a unittest.TestCase with cleanup
refactor mlab spectrum, window, and detrend functions to improve modularity, testability, and performance
implement tests for refactored mlab spectrum, windowing, and detrend functions, with 100% coverage
add more spectral plots and add new spectrum types to specgram in _axes
add tests for new spectrum types in _axes
add demo for new spectral plot types
added information regarding new spectrum functions to CHANGELOG, whats_new, and api_changes
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Merge pull request #2522 from toddrjen/spectrum

Add additional spectrum-related plots and improve underlying structure
fix removed api change regarding spectral functions
Added methods to control theta position of r-ticklabels on polar plots
Fixed typo in TimerWx
Merge branch 'master' of github.com:matplotlib/matplotlib

* 'master' of github.com:matplotlib/matplotlib: (90 commits)
  added information regarding new spectrum functions to CHANGELOG, whats_new, and api_changes
  add demo for new spectral plot types
  add tests for new spectrum types in _axes
  add more spectral plots and add new spectrum types to specgram in _axes
  implement tests for refactored mlab spectrum, windowing, and detrend functions, with 100% coverage
  refactor mlab spectrum, window, and detrend functions to improve modularity, testability, and performance
  add CleanupTestCase, a unittest.TestCase with cleanup
  add mlab tests for new spectrum types, window and detrend functions, and greatly expand existing tests
  add more spectrum functions and add new spectrum types to specgram in mlab.py, and clean up window and detrend functions in mlab.py
  Fix for compiling ttconv in extern directory
  cast argv to unicode before testing
  Move external libraries to 'extern' directory
  Minor doc fixes
  Fix encoding issues when font name contains non-ascii characters
  Fix writing to all manner of StringIO-like objects in PS backend.
  add new ps backend test file in `__init__.py`
  BUG: Fixed object type missmatch in SymLogNorm
  add failing test: savefig(StringIO(), format="ps")
  Adding a missing 'b' back into two 'bbox_' kwargs
  Fix build
  ...
Various path effects related updates.
Merge pull request #2514 from tacaswell/mpl_toolkit_pep8

Mpl toolkit pep8