Check that dynamic array length does not exceed overall message length

[jkohvakk]

Rammbock blindly believes the length of a dynamic array. It does not even check if it fits to overall message length. This lead into a hard-to debug problem where the memory of Python virtual machine was exhausted when the production code left the dynamic message length field uninitialized.

There should be at least a check for dynamic array size being smaller than overall message length. Probably also a global limit for message length which one could optionally set when importing Rammbock.

[jussimalinen]

Finally going through the issues again.. :P Yeah, I think settings a hard limit at the message length should be pretty safe.

I will be making a new release as soon as other projects let me.