All hardcoded addresses on the epiphany memory could be moved to the stack

[Tombana]

The bsp variables (syncstate and so on) are now at hardcoded addresses. Instead we could put all of those in a bsp_core_state struct and only communicate the struct address over to the host core once.

When implementing proper memory allocation functions for the epiphany cores this would probably simplify things as it removes all hardcoded addresses.

[Tombana]

• First check if global variables are stored at the binary (from 0x0000 and up) or on the stack (from 0x8000 down). If they are at the binary, that means their location is the same for every core and therefore we can move all the bsp variables to global variables. With this method, the host program does not even have to keep track of where the different cores store the variables. This is a lot neater than the current hardcoded solution.
• Furthermore we have to implement a malloc that allocates memory at the lower addresses, and it should give a warning when there is not enough space between the lower addresses and the stack (which is at the upper addresses).

[Tombana]

This was fixed after we figured out how the shared (external) memory worked and behaved. Malloc remains to be done (different issue).