Fix case when field is not on request

asUnicode(REQUEST.get(fieldname)) returns the string "None" if
fieldname is not on request.

Don't test for stuff like None and '' if that is irrelevant, it's just
noise.
Tidy column creation.

Don't put invalid values into the option list just to validate them.
Don't redefine a default value, just specify the proper default.
Don't make something a keyword parameter if its absence is a bug.
Opportunistic fix to security declaration
Add FormMethod form field with default POST
Whitespace
Render method and enctype in forms
Add 'Auto' (default) option

Create an accessor for the FormMethod form field to handle Auto.
Comment: should the read template always use GET?

Or should it honour the form method?
Test that chosen form method is being rendered

Both for form and for any datagrid on the form.
Get rid of extra logging
Make datagrid tojson always use GET

It doesn't change anything serverside.
Also give the datagrid script an id, can't hurt.
Match datagrid javascript using regexp

This shows how to do per-datagrid-field matching.
If the datagrid method is always going to be GET, don't check it

If it turns out we want tojson to sometimes POST, we can put it back.
fix missing encoding on exportCSV view
Whitespace
Make AJAX requests match the method of the form they're on

This is the simplest way to be able to choose the AJAX method a form
should use, e.g. if the AJAX calls need to use POST because of a
very bulky form.

It means that AJAX will sometimes use POST unnecessarily. We can
revisit this later.
Put back the test for AJAX method

TODO: still need a test for computehidewhens
Merge pull request #391 from pretaweb/datagrid-get

changed POST to GET for datagrid read view
Merge pull request #397 from jpcw/github-main

fix missing encoding on exportCSV view
Line things up nicely