Remove references in index iterator interface

This avoids checks.

QueryPolicy::NodeGetAttribute(): Get the type too

QueryParser: The last_modified index is time_t

* Changed value type from B_INT64_TYPE to B_INT32_TYPE.
* Changed QueryPolicy::NodeGetLastModifiedTime() return value from
bigtime_t to time_t.

QueryParser: Explicitly suspend/resume iterators

Extended policy by IndexIteratorSuspend() and IndexIteratorResume()
methods that are invoked for the index iterator by Query::GetNextEntry()
after entering respectively before exiting.

Add Query class and query management in Volume

Remove references in index iterator interface

This avoids checks.

QueryPolicy::NodeGetAttribute(): Get the type too

QueryParser: The last_modified index is time_t

* Changed value type from B_INT64_TYPE to B_INT32_TYPE.
* Changed QueryPolicy::NodeGetLastModifiedTime() return value from
bigtime_t to time_t.

QueryParser: Explicitly suspend/resume iterators

Extended policy by IndexIteratorSuspend() and IndexIteratorResume()
methods that are invoked for the index iterator by Query::GetNextEntry()
after entering respectively before exiting.

Add Query class and query management in Volume