Fixed #43 : BnfNodeParser: I can recognize when multiple level of ISA

Fixed #44 : BnfNodeParser: I must simplify results when multiple levels of ISA
Fixed #45 : Dynamic variables cannot be parsed at restart
Fixed #46 : Concepts variables values are transformed into list by default
Fixed #47 : SheerkaAdmin. Add min, max, mean time when restoring files

tests/non_reg/test_sheerka_non_reg_out.py

@@ -32,6 +32,7 @@ name      : foo
 key       : foo
 definition: None
 type      : None
+hash      : 16f7fbb8bc509b8c652edaf3d0c0457d15a37f0a862fbe03fa357b0c77249c46
 body      : 1
 where     : None
 pre       : None
@@ -44,6 +45,7 @@ name      : foo
 key       : foo
 definition: None
 type      : None
+hash      : 7036cd5ffa9294d2e1dc9bf9c9bbe2783ace5cf7f423bfce9b28c8d33c0d1d0c
 body      : 2
 where     : None
 pre       : None