Pandas table reading recognizes delimiters besides commas

Closes #238
Histogram subsets snap to bin edges

Closes #242
Merge pull request #334 from ChrisBeaumont/238

Pandas table reading recognizes delimiters besides commas
Merge pull request #336 from ChrisBeaumont/242

Histogram subsets snap to bin edges
Properly restore scatter view limits.

Closes #254
Handle Empty slice aggregation.

Closes #326
Merge pull request #339 from ChrisBeaumont/326

Fix empty slice aggregation
Merge pull request #338 from ChrisBeaumont/254

Fix scatter plot axis limit restoring
Add mailing list link to docs
Merge pull request #340 from ChrisBeaumont/doc

Add mailing list link
Prevent unnecessary draws during image subset updating.

Closes #337
Merge pull request #344 from ChrisBeaumont/337_2

Prevent unnecessary draws during image subset updating.
Fix facet bug on PyQt4

Add tests

Closes #335
Always draw show help
Change pip command
Merge pull request #345 from ChrisBeaumont/335

Fix facet bug
Merge pull request #346 from ChrisBeaumont/showhelp

Always render drag data helper
Interpolation=nearest in PV slices
Slice documentation
Update mri image