Convert some functions from static to non-static.

At the moment, this is a step backwards, but it will be helpful
when game_events.cpp gets split into pieces.
Expand the use of anonymous namespacing.

Several functions formerly declared "static" have had "static"
removed and placed inside an anonymous namespace (one exception:
for bool events_init(), "static" was changed to "inline" instead
of being dropped).

Several type definitions not needed outside game_events were moved
into anonymous namespaces.

The indentations are not pretty to make the "real" changes easier
to spot. I'll prettify the formatting when I split this file (which
I plan to do soon).
Expand namespace game_events to cover everything in game_events.cpp.

The indentations are not pretty to keep whitespace changes from
clogging the diff. I'll prettify the formatting when I split this
file (which I plan to do soon).
Some modularizations intended to ease splitting this file.
Some wrapper functions to aid the planned split of game_events.?pp.
Refactor manager_running as manager::running().
Some more wrapper functions to aid the planned split of game_events.
Reroute access to event_handlers so it goes through manager.

This is preparation for splitting game_events.cpp.
Split game_events.cpp.

VC and XCode projects still need to be updated.