Arena bytes alloced

[rfmineguy]

What? Added arena_bytes() function that counts up how many bytes are allocated in the arena Why? I wanted to be able to easily see how much memory was allocated over the course of using the arena. How? Traverse through the regions and tally up all of their counts Testing I totaled up the allocations and made sure the displayed byte count was accurate.

Thank you for making such useful and simple libraries for us all to use!