Nsec sign changesets

This shall speed up small updates to big signed zone.

The previous procedure is:

• recreate all the NSEC(3) records in the zone
• compare to the existing NSEC(3) records, making a diff
• sign this diff

The new procedure is:

• recreate only NSEC(3) records (neighbouring to) records mentioned in the changeset
• sign the changed records

The observed total speed-up of a little zone update to a huge signed zone was around 15%, but there are also other problems not related to NSEC(3) chain reconstruction.

Fixes #119 (closed)

added 64 commits

• 514dcf62...47410bd2 - 51 commits from branch master
• ccf819af - nsec(3) recreation over changesets implemented
• a0324d70 - contents: fixed zone_cotents_empty()
• a65a70a4 - zone: fixed rare segfault on update
• 3adb0ae0 - fixup1
• 28b9f0f3 - fixup2
• f4bfd1a2 - NSEC tree update: test
• 7ce8f600 - contents: removed wrong optimization
• edc8e3ae - xxx
• 6cbaeb67 - yyy
• 2dcd3a03 - xxx2
• 7670f636 - zkurveny odsazeni
• 5523fe9d - nsec3: canceling out changes in changesets
• 1a54677b - yyy2

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unmarked as a Work In Progress

changed the description

added 27 commits

• 11732693...c3984588 - 17 commits from branch master
• 36ec850d - nsec(3) recreation over changesets implemented
• 4fddf41e - contents: fixed zone_cotents_empty()
• 2c5ed429 - zone: fixed rare segfault on update
• 3d2851ce - NSEC tree update: test
• bce21124 - contents: removed wrong optimization
• 49f91ac3 - nsec3: canceling out changes in changesets
• 1fb7e5e8 - load: avoid resalt after dnssec even on load
• f2a87de2 - unconfuse clang analyzer
• d5318ea7 - nsec chain: a little log
• e917fabe - nsec update: fixed re-signing bitmap change 2

Compare with previous version

added 6 commits

• 139e95be - nsec(3): re-creation over changesets implemented
• 4f843f33 - contents: fixed zone_cotents_empty()
• 319511c6 - zone: fixed rare segfault on update
• 88d2b6df - tests-extra: add NSEC tree update test
• 2e06c717 - contents: removed wrong optimization
• 85c9d7fe - load: avoid resalt after dnssec even on load

Compare with previous version