wmllint: report stored units never unstored or cleared

Keys from the dictionary of stored units are removed as the unit is
unstored or its variable cleared. However, I found that one character in
Legend of Wesmere, Urudin, is stored but apparently never unstored/cleared.
I figure it's best to report such cases.

This message does not include helpful information like the filename,
because that data was never stored in the dictionary. The dictionary was
designed on the presumption that all entries would have a matching unstore/
clear event, and I didn't think of this warning until I saw there was an
anomalous case. Those who get this error will just have to use grep!
SotBE S9: make river edge terrain slightly less favorable for player
SotBE S9: force AI to attack enemies 1 XP from leveling

.. so that it is not possible to block key positions with such units.
SotBE S9: turn off gold saving for AI side

We want Shan Taum to throw all his forces at the player at once.
This can likely be reverted in a few days when/if the AI default is
changed, but for now it is still necessary.
SotBE S9: slight adjustment of initial village ownerships

Give Shan Taum all villages except those very close to Kapou’e’s keep.
SotBE S9: more starting gold for player

The player used to start this scenario with a lot of carry-over gold,
while now there is almost none.
SotBE S10: fix AI target filters

These are SUFs, so type=Saurian does not match anything.
[wmlunits] Filter out eras from dependencies
Make handle_external_event's declaration unconditional

The function is always implemented, so it should always be declared.
Merge branch 'master' of github.com:wesnoth/wesnoth-old
Xcode project: add FIFODIR to preprocessor macros

… in order to avoid a compiler warning.
Remove a wmllint spelling exception that doesn't belong

See commit 53d7c53df04a53e7bac87e3794b56dad28db140f.
Xcode project: remove Wesnoth_Prefix.pch from 'Prefix Header' setting

Apparently it is not needed any more and this removes the last compiler
warning.
 Xcode project: don't show warnings for third-party code (release build)

This was already done for the debug build in commit
8567a0d616d323cc74c61fd5d8ef83e025f22c42, added for the release build
as well here.
RCA AI: revert gold saving default back to 'off'

This was discussed both on the wesnoth-dev mailing list and on the
forums and the overall consensus was that it should be off, although
some scenarios will benefit from it.  It should be enabled specifically
in such scenarios as they are identified.
Reference:
https://mail.gna.org/public/wesnoth-dev/2014-01/msg00001.html
and links therein
Update release notes and changelogs with gold saving default change
SotBE S2 & S9: remove code that turns off gold saving

This is now the AI default again.
SotBE S1: enable AI gold saving

The scenario is both harder and more interesting this way and was
rebalanced with gold saving on before the AI default was changed.
Xcode project: set architecture to i386

This is required for the included libs (pango, cairo, etc.).  The
libraries should be updated at some point, but until that happens this
is what needs to be used.
Xcode project: set gcc version to Xcode default for wesnothd

This was already done and accidentally committed together with
d9659f69b4a7d5b2d8a2b1ef9acab08d291c885f for Wesnoth