- Process now optionally wraps stdout/stderr from child process to
  circumvent a python bug
- Added windows error number for port-in-use check
- fixed segv caused by lost QImage input in pyside

 - Avoid using authkey on windows; seems to be broken
 - Included yet another method of accessing shared memory as QImage

Workaround is for ViewBox to see whether its scene has changed every time it paints.

Fixes: 12

Fixes #10

Faster import of PyQtGraph.

* RawImageWidget (and thus OpenGL) isn't imported by default anymore.
* scipy.stats.scoreatpercentile is replaced by numpy.percentile.

This commit has not been tested as the example runner is currently
broken.

 - GraphItem reports pixel margins to improve auto-range
 - ViewBox.setRange is more careful about disabling auto range for axes that are set

  - setRange now only affects target range
  - updateViewRange only affects view range
  - updateMatrix only affects childGroup transform
  - updateMatrix is only called before a render

Pathway now looks like:
        setRange -> updateViewRange -> matrix dirty -> ...
                                    -> sigRangeChanged

        ... -> prepareForPaint -> updateAutoRange, updateMatrix if dirty

 - GraphicsView.render now correctly invokes GraphicsScene.prepareForPaint
 - Fixed RemoteGraphicsView renderer to use new PyQt QImage API.
 - multiprocess.Process now pipes stdout/err directly to console when in debugging mode

  - ROI updates on sigTransformChanged
  - ViewBox is more careful about accepting all auto-range changes up to the point it is disabled, even if the auto-range calculation is deferred.

    setRange -> updateViewRange -> matrix dirty
                            -> sigRangeChanged

    ... -> prepareForPaint -> updateAutoRange, updateMatrix if dirty

    Fixed improper tick spacing and axis scaling
    This requires an API change:
     - AxisItem.setScale(float) has the usual behavior
     - AxisItem.setScale(None) is deprecated (but still works). Instead use:
     - AxisItem.enableAutoSIPrefix(bool) to enable/disable SI prefix scaling
    Also makes the API more intuitive since these features are now accessed and implemented independently.

fixes #4

This requires an API change:
 - AxisItem.setScale(float) has the usual behavior
 - AxisItem.setScale(None) is no longer allowed. Instead use:
 - AxisItem.enableAutoSIPrefix(bool) to enable/disable SI prefix scaling
Also makes the API more intuitive since these features are now accessed and implemented independently.

Merge remote-tracking branch 'kif/master' into develop

Conflicts:
	pyqtgraph/pgcollections.py

Use the official backport

- Removed inf/nan checking from PlotDataItem and PlotCurveItem; improved performance
- Added 'connect' option to PlotDataItem and PlotCurveItem to affect which line segments are drawn
- arrayToQPath() added 'finite' connection mode which omits non-finite values from connections

- Added 'connect' option to PlotDataItem and PlotCurveItem to affect which line segments are drawn
- arrayToQPath() added 'finite' connection mode which omits non-finite values from connections

Update README.md

correct markdown

Add .gitignore and .mailmap