remove deprecated API before the release

[andrewrk]

This is a reminder to search the std lib for "deprecated" and remove all the deprecated API about 1-2 weeks before the next release.

[andrewrk]

OK see the above linked commit for what was done for the 0.6.0 release.

I left some things alone, since they require a bit more care and attention.

I also went ahead and did all the C/Z suffix change. The reason for that is that we don't want to imply something depends on C or is C related when actually it has to do with, e.g. the OS ABI or other reasons.

Feel free to use this issue to ask for help when upgrading code; it should be straightforward since I left @compileError messages for everything.

[andrewrk]

Skipping this for 0.7.0 due to out of time.