Codechange: Spell 'Viewport' consistently

Some places in the codebase misspell 'Viewport' as 'ViewPort' or 'view_port'.
This patch makes everything consistent.

Codechange: Use cached town, station, industry names for list window sorting

This is to avoid needing to expensively regenerate name strings on
every comparison when sorting by name in the town/station/industry
list windows.

Fix: Non-deterministic name sorting in industry directory window

In the case where multiple industries have the same name, sorting
in the industry directory window is non-deterministic.
This results in the order changing on each re-sort, and is noticeable
when the industries have different production or transported values.

Codechange: Switch DropDownList to directly use std::vector, thus making AutoDeleteSmallVector obsolete.

DropDownListItem are strongly managed using std::unique_ptr to ensure leak-free handling. Appropriate use
of move-semantics make intent a lot clearer than parameter comments and allows the compiler to generate
copy-free code for most situations.

Fix #7384: Industry Chain tooltips did not display on right-click.

This is fixed by handling the new Window::OnTooltip() event instead of OnHover()

Fix 8859381: Display of requires/produces in Build Industry window

Change the window to use a dynamically generated string of cargoes,
instead of one of a few fixed-length lists. With up to 16 cargoes
on each list, having 16 with the only difference how many are listed
seems like a bad maintenance idea.

(svn r27751) -Feature: Display cargo suffix of accepted cargoes in industry view based on cb37 result type.

Industry-sets that have no stockpiling get better control over the displayed accepted cargo information.
- result 0401 only prints the accepted cargo
- results 0800-0BFF prints the accepted cargo and a string (but not the amount)

(svn r23525) -Codechange: make Window::flags4 WindowFlags instead of uint16, with only values known in WindowFlags (and move out 2 timers to their own variable)
-Codechange: rename Window::flags4 to Window::flags
-Codechange: move some non-inline functions from .hpp to .cpp