Overflowing the memory

[ben-page]

My application was intermittently overflowing the memory store.

What I discovered is that Policy_opa_malloc and Policy_opa_heap_ptr_get will automatically grow (add pages) the memory store, but _envMemory.WriteString() does not - for obvious reason.

So if FastEvaluate() is called when _dataHeapPtr is near the end of the memory store, it can overflow the store. I created a PR to simply check the memory capacity and grow as necessary.

I also noticed that the memory allocated for the initial GetData wasn't reused if different data was loaded.

[ben-page]

#36