Crash on wrong breakpad output

CrashDragon crashes if it receives wrong output from breakpad.

panic: runtime error: index out of range

goroutine 138 [running]:
code.videolan.org/videolan/CrashDragon/processor.processReport(0x2c4d455af91d363e, 0xcb85141336d2d48a, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, ...)
        /home/videolan/go/src/code.videolan.org/videolan/CrashDragon/processor/processor.go:140 +0xbc2
code.videolan.org/videolan/CrashDragon/processor.processHandler()
        /home/videolan/go/src/code.videolan.org/videolan/CrashDragon/processor/processor.go:74 +0xfc
created by code.videolan.org/videolan/CrashDragon/processor.StartQueue
        /home/videolan/go/src/code.videolan.org/videolan/CrashDragon/processor/processor.go:25 +0x3e

If the CrashingThread field is bigger than the actual number of found Threads CrashDragon crashes.