Tweak to the cache to avoid recomputing the key.
Merge branch 'master' of https://github.com/sprowell/elision
Merge pull request #175 from sprowell/master

Avoid re-computing the key when reading from the cache.
Updated the package graph in preparation for cleaning up the library.
Moved `Context`, `RuleLibrary`, and `OperatorLibrary` and supporting stuff into the new `context` package.  Expanded all `_` import statements and cleaned them up - except for gui and related packages.
Removed file stored in wrong place.
Merge https://github.com/elision/elision
Rebuilt the compilable context stuff to better separate concerns, use the new package structure, and to create the context in stages.  Hopefully this will help with very large contexts.
Merge pull request #177 from sprowell/master

Refactoring.
Added code to do a hard stop in `_execute` when called from `read`.
Modified (further) how the compilable context is generated to make sure types are visited during traversal.
Fixed traversal to visit types.
Trying different way to get operator list that should preserve declaration order.
Corrected how the list of operators was returned.
Changed ordering of context generation - hopefully this fixes the ordering issue.
Provide a switch to repl to force calling exit to terminate all threads.
Changed the base name / filename for the compiled context.
Merge pull request #178 from sprowell/master

Working version of compilable context.
Moved `-N` flag into `ERepl`.  Want to kill of `ProcessorControl`.
Merge pull request #179 from sprowell/master

Re-located the `-N` flag.