remove dead elif in typeof_expr()
Developer documentation for adding type inference information
remove unneeded top table of contents in "extending frontend" doc
document template registry
change builtin_intrinsic to builtin in dev docs to match actual Numba usage
Merge branch 'master' of github.com:numba/numba into dev_docs
address review suggestions
put type registry first in task list
Merge pull request #691 from seibert/dev_docs

DevDocs: Extending the Front-end