Reorder Toolbar and add Guess Column Properties

[Stephen-Gates]

Desired Behaviour

A tester reports, "the validate icon appears first, but should really be executed after the column and table properties are set".

See also #134 for a suggestion to add Guess Column Properties to the toolbar.

Question

What should appear on the Toolbar and in what order?

One workflow could be:

1. open csv
2. guess column properties
3. set column properties
4. set table properties
5. validate
6. set provenance information
7. set data package properties
8. export

Another workflow could be:

1. open csv
2. validate (without a schema)
3. edit data to resolve "structural" errors (blank rows, duplicate headers, etc)
4. validate
5. guess column properties
6. set column properties
7. validate (with a schema)
8. set table properties
9. validate (with a schema and foreign keys and missing values)
10. set provenance information
11. set data package properties
12. export

Proposal

Toolbar icons in the following order:

1. guess column properties (icon to be determined)
2. set column properties
3. set table properties
4. set provenance information
5. set data package properties
6. validate (in this position to avoid breaking flow between panels using next/previous arrows)
7. export

[Stephen-Gates]

Tester 2 suggests, "the validate button should be the penultimate button (the button immediately before the 'Export')".

[Stephen-Gates]

Added 1515562 in anticipation of a change

[Stephen-Gates]

If proposal above is OK, then I've made a start on implementing #138

[Stephen-Gates]

After discussions, going with...