Setting version to 2.2
Optimize a bit unit iteration by prefetching related fields

Signed-off-by: Michal Čihař <michal@cihar.com>
Optimize index regenerating

We do not need buffered writer here as we're rebuilding full index.

Signed-off-by: Michal Čihař <michal@cihar.com>
Pass more parameters to fulltext engine

This will allow us to extend search list in future.

Issue #614

Signed-off-by: Michal Čihař <michal@cihar.com>