Removed unused submodules

.gitmodules

@@ -1,12 +1,6 @@
 [submodule "extern/StickyListHeaders"]
 	path = extern/StickyListHeaders
 	url = https://github.com/open-keychain/StickyListHeaders.git
-[submodule "extern/zxing-android-integration"]
-	path = extern/zxing-android-integration
-	url = https://github.com/open-keychain/zxing-android-integration.git
-[submodule "extern/zxing-qr-code"]
-	path = extern/zxing-qr-code
-	url = https://github.com/open-keychain/zxing-qr-code.git
 [submodule "extern/spongycastle"]
 	path = extern/spongycastle
 	url = https://github.com/open-keychain/spongycastle.git
@@ -19,9 +13,6 @@
 [submodule "extern/openkeychain-api-lib"]
 	path = extern/openkeychain-api-lib
 	url = https://github.com/open-keychain/openkeychain-api-lib.git
-[submodule "extern/SuperToasts"]
-	path = extern/SuperToasts
-	url = https://github.com/open-keychain/SuperToasts.git
 [submodule "extern/KeybaseLib"]
 	path = extern/KeybaseLib
 	url = https://github.com/open-keychain/KeybaseLib.git