Adding support for inlined ascii/utf16 strings.
This will allow us to write out strings from C much easier, as well as
flush every event when streaming as string table is required.
We'll still use the string table in most cases, as it's much more efficient
and has the ability to dedupe in the future, but this adds back the
flexibility of the old inlined strings.
Merge pull request #360 from google/char

Adding support for inlined ascii/utf16 strings.