Added Woodman traces to precompiler library to trace execution

The traces are not enabled by default. They should be useful to
track down the steps that take a lot of time and might be worth
improving.

Not surprisingly, the operation that seems to consume the most amount
of time is parsing the JavaScript code into an AST tree (with the
"range" flag set to keep track of the source code).
Fixed PatternLayout unit tests

The PatternLayout does not skip the "%n" pattern anymore even if
it is the last pattern in the string. Tests had not yet been updated.