Add the SDL exception class.
Catch the new SDL exception in the main game.
Use the new SDL exception in the SDL code.

Also:
* Fix a copy paste error in an error message.
* Make creation failures of a texture object throwing an exception.
Initialize all members

Found by coverity.
Don't dereference iterator after invalidating it

Found by coverity.
Move unicode support to its own file
Include system headers with <>, not ""
Whitespace fix
Attempt to update projectfiles
Remove gitignore in otherwise empty dir
Correct gold check comparision in recall cost

By correcting the assignment of the cost of the unit it now correctly
says whether or not the play actually has the gold to recall a unit, as
after this check it is assumed they do by the program which creates
the possibility of recalling when you have no gold, or negative gold.

Added comments so that the magic number is explained.
Merge pull request #130 from Aishiko/Add-unit-instance-recall-costs

Correct gold check comparision in recall dialog
Add missing include for windows-only files
Merge branch 'master' of github.com:wesnoth/wesnoth
Merge branch 'SDL2_exception'

Improves the exception handling for the SDL2 code.
Revert XCode changes in "Attempt to update projectfiles"

This reverts part of commit f786c2d4229ea16f6d6fbe24f557a524af74707d.
Update Xcode project
Messenger MAI: add optional [filter_second] tag

This allows selection of the escort units.
Move Micro AI auxiliary functions into their own file
Move path to Micro AI candidate actions files into variable

The purpose of this commit (and the previous) is to make it easier for
UMC authors to add functionality to the Micro AIs.