Aligned model fix

[kthakore]

Adding the guard that ensures that the model file is aligned when compiled into program memory. Without this guard the tensorarena is misaligned and libraries that add uneven bytes to program memory could cause a seg fault when the TFInterpeter is invoked. @sandeepmistry and I found out about this during the ArmDevSummit 2019.

[sandeepmistry]

Hi @kthakore,

Thanks to submitting this pull request!

There seems to be a lot more changes in this that I expected, maybe you need to apply this pull request to the following repo instead? https://github.com/arduino/AIoT-Dev-Summit-2019

[kthakore]

Ah yep! I will update both separately ;)

[kthakore]

@sandeepmistry pushed up fix in both repo's ;)

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you sign our Contributor License Agreement before we can accept your contribution.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}