Support building snapshot releases by creating tags.

If HEAD is tagged, check for "SNAPSHOT" or "DEBUG" in the tag name when
generating the version string for a build. If found, add
"-SNAPSHOT-abcdef0" or "-DEBUG-abcdef0" at the end of the version
string (where "abcdef0" is the short commit ID for HEAD).

BGMApp/BGMApp.xcodeproj/project.pbxproj

@@ -911,7 +911,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "# Append the git HEAD short ID to the build version for snapshot builds. Thanks to\n# Václav Slavík for the initial version of this: http://stackoverflow.com/a/26354117/1091063\n# TODO: Update CFBundleVersion as well?\nTAG=$(/usr/bin/git tag --points-at HEAD 2>/dev/null)\nif [[ $? -eq 0 ]] && [[ \"${TAG}\" == \"\" ]]; then  # If HEAD isn't tagged, this is a snapshot build.\n    HEAD=$(/usr/bin/git rev-list HEAD --max-count=1 --abbrev-commit)\n    INFO_PLIST=\"${BUILT_PRODUCTS_DIR}/${INFOPLIST_PATH}\"\n    if [[ \"${CONFIGURATION}\" != \"Release\" ]]; then\n        TYPE=\"DEBUG\"\n    else\n        TYPE=\"SNAPSHOT\"\n    fi\n    if [[ -f \"$INFO_PLIST\" ]]; then\n        CURRENT_VERSION=$(/usr/libexec/PlistBuddy -c \"Print :CFBundleShortVersionString\" \"${INFO_PLIST}\")\n        BASE_VERSION=$(/usr/libexec/PlistBuddy -c \"Print :BGMBundleVersionBase\" \"${INFO_PLIST}\" 2>/dev/null)\n        if [[ $? -ne 0 ]] || [[ \"${BASE_VERSION}\" == \"\" ]]; then\n            BASE_VERSION=\"${CURRENT_VERSION}\"\n            /usr/libexec/PlistBuddy -c \"Add :BGMBundleVersionBase string ${BASE_VERSION}\" \"${INFO_PLIST}\"\n        fi\n        NEW_VERSION=\"${BASE_VERSION}-${TYPE}-${HEAD}\"\n        if [[ \"${NEW_VERSION}\" != \"${CURRENT_VERSION}\" ]]; then  # Only touch the file if we need to.\n            /usr/libexec/PlistBuddy -c \"Set :CFBundleShortVersionString ${NEW_VERSION}\" \"${INFO_PLIST}\"\n        fi\n    fi\nfi";
+			shellScript = "# Append the git HEAD short ID to the build version for snapshot builds. Thanks to\n# Václav Slavík for the initial version of this: http://stackoverflow.com/a/26354117/1091063\n# TODO: Update CFBundleVersion as well?\n\n# If HEAD isn't tagged, or has \"SNAPSHOT\" or \"DEBUG\" in the tag name, this is a snapshot build.\nTAG=$(/usr/bin/git tag --points-at HEAD 2>/dev/null)\nif [[ $? -eq 0 ]] && ( [[ \"${TAG}\" == \"\" ]] || \\\n        [[ \"${TAG}\" =~ .*SNAPSHOT.* ]] || \\\n        [[ \"${TAG}\" =~ .*DEBUG.* ]] ); then\n    HEAD=$(/usr/bin/git rev-list HEAD --max-count=1 --abbrev-commit)\n    INFO_PLIST=\"${BUILT_PRODUCTS_DIR}/${INFOPLIST_PATH}\"\n    if [[ \"${CONFIGURATION}\" != \"Release\" ]]; then\n        TYPE=\"DEBUG\"\n    else\n        TYPE=\"SNAPSHOT\"\n    fi\n    if [[ -f \"$INFO_PLIST\" ]]; then\n        CURRENT_VERSION=$(/usr/libexec/PlistBuddy -c \"Print :CFBundleShortVersionString\" \"${INFO_PLIST}\")\n        BASE_VERSION=$(/usr/libexec/PlistBuddy -c \"Print :BGMBundleVersionBase\" \"${INFO_PLIST}\" 2>/dev/null)\n        if [[ $? -ne 0 ]] || [[ \"${BASE_VERSION}\" == \"\" ]]; then\n            BASE_VERSION=\"${CURRENT_VERSION}\"\n            /usr/libexec/PlistBuddy -c \"Add :BGMBundleVersionBase string ${BASE_VERSION}\" \"${INFO_PLIST}\"\n        fi\n        NEW_VERSION=\"${BASE_VERSION}-${TYPE}-${HEAD}\"\n        if [[ \"${NEW_VERSION}\" != \"${CURRENT_VERSION}\" ]]; then  # Only touch the file if we need to.\n            /usr/libexec/PlistBuddy -c \"Set :CFBundleShortVersionString ${NEW_VERSION}\" \"${INFO_PLIST}\"\n        fi\n    fi\nfi";
 		};
 		276972891CAFCE91007A2F7C /* ShellScript */ = {
 			isa = PBXShellScriptBuildPhase;