This commit implements list addition. A new list is allocated, and
the contents of l1 and l2 are concatenated onto the list.
This is done by extending the buffer template macro to support a
`concat` operation, which given an `other` buffer, appends all
elements of the `other` buffer to the end of the `self` buffer.
Allocations are done as needed.
We implement this additional operation, since the alternative would
be to call `reserve()` for each `write()` operation, which doesn't
seem ideal.
Issue: #55
* fixed typos in src/
* fixed typos in docs/
* fixed typos in README and tests/
* rename INITALIZE to INITIALIZE
* rename PRIMITE to PRIMITIVE
* rename moudle to module
Co-authored-by: Alexander Patel <acpatel@andrew.cmu.edu>