Adds support for the 'autocomplete' HTML attribute to HTMLTextField
(mainly for turning it off, but other values are supported as well).
Renames 'autocomplete' to 'autocomplete-data' (with temporary B/C)
in HTMLAutoCompleteSelectField to make space.
Change-Id: Ic0539d5a61d9862e670d10686adc1e41f65d908e
Codesniffer says that the `var` keyword must not be used to declare a
property and that visibility must be declared on class properties.
Change-Id: I28240aa0f394588b1df315621dbcd260c51430c1
