improve() attempted not to spend the last dollar, but screwed up when
improving more than one sector. This could bankrupt the player.
Replace the flawed code by the same simple method that is used
elsewhere: break the loop when there's not enough money left for the
current sector.
other. Ensure headers in include/ can be included in any order
(except for econfig-spec.h, which is special). New header types.h to
help avoid inclusion cycles. Sort include directives. Remove some
superflous includes.
instead of opt_DEFENSE_INFRA.
(improve): Test for it.
(show_sect_build): Show only enabled infrastructure.
(opt_DEFENSE_INFRA): Remove. Deities can edit infra.config instead.
(improve): Dumb down prompt.
of copies made by getvec(). This is safe, because the old code made
single copies and always flushed them back into the unit structures
before flushing those.
