Adding Edl button in reboot menu

Edl mode is available only on qualcomm devices and it used to fully
restore the bricked devices. I made the button available only if
TW_HAS_EDL_MODE := true like the download button. I set the edl
button to the right of the download button, so devices can support
edl button and download button. I also added the translation for
all languages.

Change-Id: I69d1058b8c050b722395c7b3da6dce1ccfbe7a91
diff --git a/variables.h b/variables.h
index 22eb5c9..3b61432 100644
--- a/variables.h
+++ b/variables.h
@@ -129,6 +129,7 @@
 #define TW_MIN_SYSTEM_SIZE          "50" // minimum system size to allow a reboot
 #define TW_MIN_SYSTEM_VAR           "tw_min_system"
 #define TW_DOWNLOAD_MODE            "tw_download_mode"
+#define TW_EDL_MODE                 "tw_edl_mode"
 #define TW_IS_ENCRYPTED             "tw_is_encrypted"
 #define TW_IS_DECRYPTED             "tw_is_decrypted"
 #define TW_CRYPTO_PWTYPE            "tw_crypto_pwtype"