v7.50

Added: Copy log file to backup folder at the end of backup.
Added: Replace the word "date" in backup name with current date.
Added: Finally busyboxed md5sum dd and tar calls.
Added: Kill all sub-processes upon exits.
Added: Ability to backup emmc partitions for MTK based devices.
Bug Fix: Incomplete backups while using compression (default) in TWRP mode.
Bug Fix: Partition size detection of emmc partitions.
Bug Fix: Notification on some devices.
Bug Fix: sd-ext detection on some devices.
Bug Fix: Could not change to folder bug in some devices, in TWRP mode.