New -host and -port args, some IPv6 support
Fix: make sure we do not override neostore.schema.db when upgrading from 2.0 to 2.1
Recognizes transactions with net zero changes as read-only

There was an issue wherea transaction with changes, although net zero
changes, would be treated as a write transaction and be committed. In a
cluster such a transaction would be treated as a read-only transaction and
so there would be a mismatch between the authoring database and the rest
of the cluster in the transaction id sequence.
Reenable test and possibly make it less flaky.
Merge pull request #2921 from davidegrohmann/2.1-fix-index-upgrade

Fix: make sure we do not override neostore.schema.db when upgrading from 2.0
Merge pull request #2922 from tinwelint/2.1-dont-commit-read-txs

Recognizes transactions with net zero changes as read-only
Improved code for moving migrated files in the store directory
Merge pull request #2920 from lutovich/2.0-improve-backup-tool-args

New -host and -port args, some IPv6 support
Merge pull request #2923 from davidegrohmann/1.9-reenable-test

Reenable test and possibly make it less flaky
Merge remote-tracking branch 'upstream/1.9-maint' into 2.0-maint
Merge pull request #2936 from davidegrohmann/merge-1.9-into-2.0

Merge 1.9 into 2.0
Merge remote-tracking branch 'upstream/2.0-maint' into 2.1-maint
Merge pull request #2940 from davidegrohmann/merge-2.0-into-2.1

Merge 2.0 into 2.1
Merge pull request #2930 from davidegrohmann/2.1-store-migration-cleanup

Improved code for moving migrated files in the store directory
Improve performance of index lookup with tx state.

Performing an index lookup in a transaction with state was implemented
as a linear scan over the transaction state. Even if the lookup from the
underlying store was fast, the performance would degrade linearly to the
size of the active transaction.
This change set improves the performance of index lookups in a
transaction in a transaction with state by building up an index-like
structure in the transaction state as well. This index state is built
for the indexes defined by the schema.
Fixes race condition in test code.

RemoteRequestMonitoringIT would fail under certain cicrumstances
due to EideticRequestMonitor not being thread safe.

This diff also improves the failure reporting on the same test case.
Merge pull request #2966 from thobe/2.1-index-tx-state

[2.1] Improve performance of index lookup with tx state.
Add suppot for migrating logs from 2.0 to 2.1

- some code cleanup and refactors
Merge pull request #2967 from davidegrohmann/2.1-migrate-logs-from-2.0

[2.1] Add support for migrating logs from 2.0 to 2.1
Handling of exceptional conditions during HA upgrade