Use null-safe string method for symbols as well as strings.
Use more performant .bytesize instead of unpack('C*').size.
Add spec demonstrating failure when a symbol contains a null character.
Merge pull request #23 from nathanaeljones/fix-strings

accept symbols with \0 in them
remove "tested on Ruby 1.8.x"

since String#bytesize is not present on older Ruby 1.8.x
adapt symbols + \0 spec title
1.1.2 pre
update changelog
Merge pull request #24 from nathanaeljones/fix-c-closure-coroutines

provide stack/state to Ruby functions
rename LightState to CallbackState
use "#{filename}:#{lineno}" as eval chunk name

closes gh-25
Add more (perhaps redundant) specs to string_spec.