CLI Buffer Sizes

[almann]

By default, the CLI tools (both ion and ionizer) have very small buffers for various things. A customer had a file, for example with a 90K byte string literal in it which causes the tool to fail with an undersized buffer error.

I patched the tools at commit 353fdee to unblock the customer, however, we really should either take the above defaults and/or make this configurable.