Development planning, Milestone 4

When the ANTLR4 tool is available in TS it's time to move on to create the target runtime plugin infrastructure.

[ ] Start with the TS runtime (antlr4ng) and work out the fundamental structure.
[ ] Next is the C++ runtime, which should be easy then.
[ ] Give AssemblyScript a try and see if we can get this working for ANTLR4. If so create a new runtime.
[ ] Write proper documentation for the new runtime plugin system and publish everything.

mike-lischke / ANTLRng