Gist::insert() is implemented with some private methods
bugs fixed: build
pointer to ParentEntry is added into inner_Entry and inner_Entry::getSubpredicates() is added to get predicates of children entries for Gist::split()
implementation notes of Gist::insert() and others
Merge pull request #7 from alinadubatovka/master

Gist::insert implementation =^_._^=
New Gist::insert() without Entries' parents. New InnerEntry without parent.

Gist::chooseSubtree(), Gist::split(), Gist::adjustKeys() are deleted and merged into Gist::insert().
PredicateHolder is implemented, it contains the only method getPredicate(). Entry inherits PredicatesHolder. Predicate::pickSplit() works with PredicateHolders.

PredicateHolder is parametrized by Predicate. Problem because of cycling dependencies! :'(
Merge pull request #8 from alinadubatovka/master

New implementation of Gist::insert() and PredicateHolder :3
Predicate fix

fixed split signature in Predicate
Concurrency: add initial versioning for search operation