* add timestamp to transaction assignment
* add reassignment delay to configuration
* refactor to multipipes
* # This is a combination of 7 commits.
# The first commit's message is:
stale transaction monitor and tests
# The 2nd commit message will be skipped:
# simplify logic
# The 3rd commit message will be skipped:
# node will assign to self
# The 4th commit message will be skipped:
# block listens for insert and update
# The 5th commit message will be skipped:
# more test coverage
# The 6th commit message will be skipped:
# test coverage
# The 7th commit message will be skipped:
# test coverage
* stale transaction monitor and tests
* update operation only returns new value
There was a problem related to the import of the module
`bigchaindb.web.views`.
The module, when imported, inizialises a new `Bigchain` instance, and
this is wrong for testing and because it's a bad practice.
I spent more or less 2h finding out the problem.
