Reinstate cppy recipe and update 3 related recipes.

[RobertFlatt]

These 4 recipes all relate to cppy.
All 4 Python packages are from the same repository https://github.com/nucleic

1. Reinstate cppy recipe, use PyProjectRecipe and latest version.

2. Update atom version to latest, and add hostpython_prerequisites

3. Update enaml version to latest, and remove patch no longer required

4. Update kiwisolver version to latest, change depends to hostpython_prerequisites,
   and change = to += to fix kiwisolver error ld: error: undefined symbol: main #3122

(Caveat: I have absolutely no clue as to how one would test enaml on Android.)

[RobertFlatt]

1. This did not fix kiwisolver error ld: error: undefined symbol: main #3122

2. There is also an issue on 32 bit targets having LONG_BIT defined as something other than 8 * SIZEOF_LONG.

[AndreMiras]

LGTM! Thanks for picking this up and for sharing all the context.
Even though not all recipes build across all arch and OS, this is still an improvement over what we had.

Would you mind documenting the known issues in the module or class docstrings of the failing recipes?
For example, in the kiwisolver module or class docstring, note that it doesn't build on macOS and link to the related issue. Similarly, for the atom recipe, you could document the error just as you did in your comment above.

Bonus points if you squash the commits into one and include the PR description in the commit message, this would ensure that valuable context is preserved in the commit history.

[T-Dynamos]

There is also an issue on 32 bit targets having LONG_BIT defined as something other than 8 * SIZEOF_LONG.

indicating it only supports 64bit architecture.