remove asserts from kowhai_utils

some platforms don't implement all the std signal lib required to use
assert (like _exit, _kill, etc), it would be nice if kowhai didnt depend
on any of these ... it seems these asserts may just have been left there
for development anyway so I think it is safe enough just to remove them
since they are all on internal (static) functions and assume they wont
happen
Merge branch 'master' into kowhai_utils_asserts
Merge pull request #36 from othane/kowhai_utils_asserts

Kowhai utils asserts
fix buffer overrun in [kowhai_]serialize_nodes

we were not always checking if a recursive call went off the end of the
buffer and since snprintf uses a size_t which is assumed to be unsigned
it thinks the buffer is huge and writes the next line (over running the
buffer), following the overrun our "if (r > dst_len)" knows we did
something wrong, but the damage is done ... this can continue in a loop
over array items which will really screw the memory after the buffer
Merge pull request #37 from othane/node_serializer

fix buffer overrun in [kowhai_]serialize_nodes