Release Backlog - A holder for high priority issues not yet assigned to a release

[jsirois]

• Multi-interpreter feature doesn't work perfectly Multi-interpreter feature doesn't work perfectly #415
• Support PEP-518 builders Support PEP-518 builders #660
• Not all changes to setup.py invalidate the cache. Not all changes to setup.py invalidate the cache. #620
• resolver bugs:
  • Dependency resolution can't handle PEP 503-style normalized package names Dependency resolution can't handle PEP 503-style normalized package names #641
  • Pex resolution does not properly constrain sdists. Pex resolution does not properly constrain sdists. #628
  • pex 1.5.1 bombs at runtime with missing deps error when extras are transitively pulled in for existing packages with concrete requirement specs in the resolve scope pex 1.5.1 bombs at runtime with missing deps error when extras are transitively pulled in for existing packages with concrete requirement specs in the resolve scope #616
  • Pex cannot correctly resolve between multiple transitive dependencies Pex cannot correctly resolve between multiple transitive dependencies #614
  • Resolve seems to be inconsistent in python 3.4 Resolve seems to be inconsistent in python 3.4 #611
  • pex fails to resolve wheels when a sdist is present in the cache pex fails to resolve wheels when a sdist is present in the cache #608