AI: Assume that other cities in range get action target immunity too

This will increase the motivation to build a wonder that makes many cities
immune to an action. Like the similar code for effects it assumes the result for
the city applies to the other cities in range. This is a lot faster than
checking if each city in range can be a target for an action and if the
situation will change if the evaluated building is built.

See patch #4627

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24717 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Don't block leaving network page by waiting metaserver scan to finish. It absolutely
must be finished only before starting a new one, or quitting entire program.

See patch #4616


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24718 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
Removed obsolete "replaced_by" field from city styles.

See patch #4630


git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24720 a0f10bec-cc02-0410-94fc-a9cfff90b4cd
AI: Effects from local range buildings could be active in 1 city

When assigning building want a local building requirement could be active in 1
city. It could also, if a local building isn't sent to the evaluation function,
be active in 0 cities.

The advantage of assuming the local range is 0 is that the AI isn't confused by
rule set bugs that result in requirements that are impossible to fulfill. A
local building requirement in a requirement list that is evaluated without a
local building would otherwise trick the AI into thinking it can get it by
building the required building.

The advantage of assuming that a local building requirement is valid in 1 city
is that it can reason about triggering effects like Upkeep_Free. It is also more
correct in general to assume a local building requirement affects 1 city. In my
view this makes up for the AI being confused by a buggy ruleset.

See bug #21852

git-svn-id: svn://svn.gna.org/svn/freeciv/trunk@24721 a0f10bec-cc02-0410-94fc-a9cfff90b4cd