* Miscellaneous tweaks & fixes
details:
+ Catch `TransportError` exception in `legacy.nim` module
+ Fix self-calling wrapper `hexaryEnvelopeTouchedBy()`
* Update documentation, logging etc.
* Changed `checkNode` batch list `seq[Blob]` => `seq[NodeSpecs]`
why:
The `NodeSpecs` type as used here is a tuple `(partial-path,node-key)`.
When `checkNode` partial paths are collected, also the node key is
available so it should be registered and not repeatedly recovered from
the database.
* Add optional begin/end trace statement in snap scheduler
why:
Allows to trace invoked entity and scheduler state variables