Consider making "persistent layering of methods" optional

Nobody has claimed this yet.

The feature implemented for #34 is useful in environments like Lively, but less so in ordinary web applications where methods are seldom or never modified. Since the additional getter call probably adds a performance overhead (which is yet to be measured...), it should be somehow configurable if that technique should be applied or not. In the latter case, the method wrapping should happen as it did before the changes to implement #34.

We could configure this behavior, for example, by adding a configure function or configuration object in the contextjs module.

Start in the contextjs module and compare the current persistent-layering behavior with the pre-#34 method wrapping described in the issue. Measure the getter overhead, then define and document a configuration approach whose disabled behavior matches the earlier wrapping semantics.

Written by the indexing model from the issue text.