Change version to 1.8.7.1

Increase version to 1.8.7, update NEWS

Fix sidebar pending queries counter after 738c10d

The optimization changes of 738c10d could leave the m_pendingQueries
counter in inconsistent change, because it was resetted to 0 too early.
In practice, this would cause OnQueriesFinished() to be called when they
weren't yet finished.

Update NEWS

Fix broken 29fd612

The 29fd612 commit accidentally only changed the corresponding comment,
but didn't actually change the _code_. Oops.

Release 1.8.3

Version 1.8.2

Version 1.8.1

Release 1.8

Version 1.7.7