MB-9771 Exchange viewgroup header via stdin/stdout

For view index incremental updater, change has been made
to receive viewgroup header via stdin and send back new header
after performing incremental updates via stdout. This avoids
writing of intermediate index header from native updater.

Change-Id: I68aecd2cb305a45a46f3d3fb45c705f2eab72ccc
MB-9771 Perform view ops sorting in incremental index updater

Change-Id: Ib7a135d68504137c27535df49f402e5ddf5102b0
Fix error codes in native index builder and index cleaner

Change-Id: I8dc0bb742ae51fb3112f038969ef00d81aae22ce
Remove redundant code for getting error string

Change-Id: I6369a14895d71fed61e2a45fe8d9aa833374e631
Fix view comparator for range lookups

Comparator should return zero if any of the keys
are of zero in length.

Change-Id: I963dcab73da18cc2d4eb25e393581e8341452cf4
Move arena_copy_buf method to util.cc

Change-Id: I2a80750038ce110a41f6903295f0655ae27468dc
MB-9835 Add native viewgroup compacter

Implementation of native view index compacter.
The native program receives viewgroup header info through stdin
and it creates a new index file and recreates all view btrees
and id btree. The resulting index header is written out to stdout.

Change-Id: I8f8f43c6fd7afb63db45d0b13eb7110ec8055cd7