2847 - The great rename of 2013

Now we should be using the same naming conventions in both C and wart
code: underscores for everything, globals capitalized, macros and
constants in all-uppercase.

The hope is that the type-vs-variable divide is not that important, and
that highlighting globals like in lisp allows us to use them more
tastefully rather than ban them outright.
2848
2849
2850
2851

Bugfix: can't check absence of multiple lines in trace.
2852 - rename layer to frame

Time to get more disciplined about names:
  a) Wart will support three Views.
  b) Top-down, the program decomposes into Levels of functions.
  c) Over time levels accumulate Layers of concerns.
  d) Recursive executions of a single function operate in different Frames.

So far our layers have been in distinct functions, so the Level vs Layer
distinction isn't fleshed out.