Hastily implemented persistent deque.
push/pop Front/Back functions (some errors exist)
Looks like some push/pop errors fixed.
+ packages
+ Kaplan-Okasaki-Tarjan persistent deque (bugged)
+ Buffer helper
Bug NullReference fixed. DequeKOT push/pop fixes.
DequeKOT push/pop bugs fixed
Some snowmen came: ☃
Merge pull request #1 from sergeyromanov/master

Greets from Ekb
+ tests for deque.
Merge branch 'master' of github.com:happanda/adv_algo
Fixed Deques bug of exception on empty children hierarchy.
Fixed tests.
Fixed test errors.
Can run all tests even if one throws.
Removed unnecessary try-catch.
+ interactive program to work with the DequeKOT
+ base interface Deque. Fixed PersistentDeque pop bug.
+ benchmark methods (should make more customizable).
Replaced Buffer with three references in DequeKOT.
Refactoring; updated benchmark.