Fix #250

• Fix #250 (closed) by adding the RPC module for Grandpa.

Note: proveFinality call will only work after the first authority set change.

end2end-tests/cucumber-features/distance_fail.feature

+@genesis.bad_distance
+
+Feature: Distance fail
+#
+# WoT:
+#
+# H<->G<->E<->D<->C-->B
+# ^   ^           ^   ^
+#  \ /             \ /
+#  v v             v v
+#   I               A
+#
+# Every member is referee. Referee count = 8; 80% = 6.4
+# Certs from Alice and Bob do not ensure the fulfilling of the distance rule
+# because the newcomer would reach only 6 members up to G.
+
+
+  Scenario: an unvalidated member fails the distance rule
+    Then treasury should contain 1 ĞD
+    When alice sends 7 ĞD to ferdie
+    Then alice should have 0 ĞD reserved
+    Then alice should have 199 cĞD
+    When bob sends 750 cĞD to ferdie
+    When 15 block later
+    When alice creates identity for ferdie
+    Then ferdie identity should be unconfirmed
+    Then ferdie should be certified by alice
+    When ferdie confirms his identity with pseudo "ferdie"
+    Then ferdie identity should be unvalidated
+    When 3 block later
+    When bob certifies ferdie
+    Then ferdie should be certified by bob
+    Then ferdie should have 0 ĞD reserved
+    Then ferdie should have 1449 cĞD
+    When ferdie requests distance evaluation
+    Then ferdie should have 10 ĞD reserved
+    Then ferdie should have 449 cĞD
+    When 7 blocks later
+    Then treasury should contain 102 cĞD
+    When alice runs distance oracle
+    When 7 blocks later
+    Then ferdie should be certified by alice
+    Then ferdie should be certified by bob
+    # The distance rule is failed
+    Then ferdie identity should be unvalidated
+    # Ferdie got his reserve slashed
+    Then ferdie should have 0 ĞD reserved
+    Then ferdie should have 449 cĞD
+    # Slashed amount is transfered to treasury
+    Then treasury should contain 1102 cĞD