Data Importer usability improvements

This minor release of Data Importer brings a number of small but useful improvements:

Datatype detection
: For properties created using
Select from file
, we now scan the first few rows of a file to make an educated guess on the datatype

Node ID selection
: We've tweaked the node id selection logic so that we'll now only choose a column ending
id
as a node id if it's the only such column in a file.
Problem files:
Duplicated or empty column names in your files have the potential to cause unexpected behaviour or load errors. We now make it clear which files are affected allowing you to fix them before continuing.