Vertical labels in mosaic and sieve diagrams.
Fix a divide by zero error, more accurate level of detail computation.

Qt's levelOfDetailFromTransform seems to flush subnormals to zero.
Fixed template download url.
Removed empty space (for "unknown" values) in sieve diagram.
Format the discretized labels using 'number_of_decimals'.
Separated the implementation of to_val and value_from_str_add.
Fixed a wrong assert condition.
Merge pull request #127 from markotoplak/verticallabels

Vertical labels in mosaic and sieve diagrams.
Merge pull request #130 from ales-erjavec/disc-format

Discretized labels formating
Avoid crashing on irregular inputs.
Correct documentation for discretization methods.
Use less then the specified (max) number of intervals, when some would be empty.
Add unit test.
Change version to 3.2-dev.
Use regular Qt's tooltips in scatterplot graph.
Clear/reset axis tick labels.
Use a smaller font for axis tick labels.
Fixed an AttributeError in getConditionalDistributions.
Fixed sending 'None' selections after disconnecting inputs.
Test continuous.