SFML-Cocoa is now part of the cmake-based examples

Removes Xcode project
Fixes a crash and
Silences system alerts in this example

examples/cocoa/CMakeLists.txt

@@ -0,0 +1,63 @@
+
+set(SRCROOT ${PROJECT_SOURCE_DIR}/examples/cocoa)
+
+# all source files
+set(SRC ${SRCROOT}/CocoaAppDelegate.h
+        ${SRCROOT}/CocoaAppDelegate.mm
+        ${SRCROOT}/NSString+stdstring.h
+        ${SRCROOT}/NSString+stdstring.mm
+        ${SRCROOT}/main.m)
+
+# all XIB files
+set(XIBS MainMenu)
+
+# all resource files
+set(RESOURCES ${SRCROOT}/resources/logo.png
+              ${SRCROOT}/resources/icon.icns
+              ${SRCROOT}/resources/blue.png
+              ${SRCROOT}/resources/green.png
+              ${SRCROOT}/resources/red.png
+              ${SRCROOT}/resources/Credits.rtf)
+
+# define the cocoa target and customize it
+add_executable(cocoa MACOSX_BUNDLE ${SRC} ${RESOURCES})
+set_source_files_properties(${RESOURCES} PROPERTIES
+                            MACOSX_PACKAGE_LOCATION Resources)
+set_target_properties(cocoa PROPERTIES
+                      MACOSX_BUNDLE_INFO_PLIST ${SRCROOT}/resources/Cocoa-Info.plist)
+target_link_libraries(cocoa "-framework Cocoa -framework Foundation" 
+                            sfml-system sfml-window sfml-graphics)
+
+# compile XIB files
+find_program(IBTOOL ibtool HINTS "/usr/bin" "${OSX_DEVELOPER_ROOT}/usr/bin")
+if(${IBTOOL} STREQUAL "IBTOOL-NOTFOUND")
+  message(FATAL_ERROR "ibtool is required to compile .xib files but wasn't found.")
+endif()
+set(RESOURCE_PATH "cocoa.app/Contents/Resources")
+set(XIB_OUTPUT_PATH "${RESOURCE_PATH}/")
+set(XIB_INPUT_PATH "${SRCROOT}/")
+foreach(XIB ${XIBS})
+    add_custom_command(TARGET cocoa
+                       POST_BUILD 
+                       COMMAND ${IBTOOL} --errors
+                                         --output-format human-readable-text 
+                                         --compile ${XIB_OUTPUT_PATH}/${XIB}.nib 
+                                         ${XIB_INPUT_PATH}/${XIB}.xib
+                       COMMENT "Compiling ${XIB}.xib")
+                       # deactivated options : --warnings --notices
+endforeach()
+
+# add install rule
+install(TARGETS cocoa
+        BUNDLE DESTINATION ${INSTALL_MISC_DIR}/examples/cocoa
+        COMPONENT examples)
+
+#
+# define the cocoa target
+# sfml_add_example is not compatible with application bundles !
+#
+#sfml_add_example(cocoa
+#                 SOURCES ${SRC}
+#                 DEPENDS sfml-system sfml-window sfml-graphics)
+#
+