Problem: need linking to curve crypto library

Solution: add libsodium to list of defined projects
Merge pull request #96 from hintjens/master

Problem: need linking to curve crypto library
Problem: Class API models do not support constants
Solution: Add constants to models and generated @interface headers
Merge pull request #97 from jemc/master

Problem: Class API models do not support constants
Problem: No way to model abritrary private headers
Solution: Honor `private = "1"` in header items in project model
Merge pull request #98 from jemc/master

Problem: No way to model arbitrary private headers
Problem: lack support for zproto state machine animation

The zproto server/client state machines provide an animation option
which shows the state transitions. This is helpful for debugging any
errors in the state machines. This is enabled by passing -v to the
selftest (which passes a verbose argument to server/client classes).

Solution: add 'make animate' target that does a 'make check' with
verbose option.
Merge pull request #99 from hintjens/master

Problem: lack support for zproto state machine animation
Problem: The need of a license.xml isn't mentioned in the README
Solution: Explain how to include a license and what it is used for
Problem: Forgot to generate README.txt in README.md
Solution: use gitdown to generate it