Add MACContext and make HMAC and CMAC to use it.
Ooops.
Add docs.
Add missing period.
Remove algorithm property from MACContext and alias CMACContext.
Add to changelog. Document deprecation.
Add to changelog. Document deprecation.
A few docs formatting nits
Merge pull request #1423 from alex/pr/1396

Add MACContext and switch HMAC and CMAC to use it