Add 2 network charts to page header

-Hashrate chart is populated from get_hashrate
-Difficulty chart is populated from get_difficulty
-Added a networkhistories collection to hold the new network data
-Index sync and resync functions now check for and update network history data at the end of the sync process
-restore_backup.sh and delete_database.sh scripts now drop the new networkhistories collection
-Added a new javascript library chartjs-plugin-crosshair which adds crosshair functionality to the new chart.js line charts
-Added new settings to settings.json for controlling things like collecting network_history data, independently enabling/disabling the network charts and changing colors of various aspects of the charts
-Updated README to introduce the network charts and added a line for the chartjs-plugin-crosshair library

scripts/delete_database.sh

@@ -21,6 +21,7 @@ sudo touch "${SCRIPT_PATH}/del.tmp" && mongo <<EOF
 use explorerdb
 db.addresses.drop()
 db.addresstxes.drop()
+db.networkhistories.drop()
 db.coinstats.drop()
 db.heavies.drop()
 db.markets.drop()

scripts/restore_backup.sh

@@ -34,6 +34,7 @@ sudo mongo <<EOF
 use explorerdb
 db.addresses.drop()
 db.addresstxes.drop()
+db.networkhistories.drop()
 db.coinstats.drop()
 db.heavies.drop()
 db.markets.drop()

scripts/sync.js

@@ -339,11 +339,14 @@ if (database == 'peers') {
                                           db.get_stats(settings.coin.name, function(nstats) {
                                             // check for and update heavycoin data if applicable
                                             update_heavy(settings.coin.name, stats.count, 20, settings.blockchain_specific.heavycoin.enabled, function(heavy) {
-                                              // always check for and remove the sync msg if exists
-                                              remove_sync_message();
+                                              // check for and update network history data if applicable
+                                              update_network_history(nstats.last, settings.network_history.enabled, function(network_hist) {
+                                                // always check for and remove the sync msg if exists
+                                                remove_sync_message();
 
-                                              console.log('reindex complete (block: %s)', nstats.last);
-                                              exit();
+                                                console.log('reindex complete (block: %s)', nstats.last);
+                                                exit();
+                                              });
                                             });
                                           });
                                         });
@@ -383,11 +386,14 @@ if (database == 'peers') {
                                 db.get_stats(settings.coin.name, function(nstats) {
                                   // check for and update heavycoin data if applicable
                                   update_heavy(settings.coin.name, stats.count, 20, settings.blockchain_specific.heavycoin.enabled, function(heavy) {
-                                    // always check for and remove the sync msg if exists
-                                    remove_sync_message();
+                                    // check for and update network history data if applicable
+                                    update_network_history(nstats.last, settings.network_history.enabled, function(network_hist) {
+                                      // always check for and remove the sync msg if exists
+                                      remove_sync_message();
 
-                                    console.log('update complete (block: %s)', nstats.last);
-                                    exit();
+                                      console.log('update complete (block: %s)', nstats.last);
+                                      exit();
+                                    });
                                   });
                                 });
                               });
@@ -580,6 +586,15 @@ function update_heavy(coin, height, count, heavycoin_enabled, cb) {
     return cb(false);
 }
 
+function update_network_history(height, network_history_enabled, cb) {
+  if (network_history_enabled == true) {
+    db.update_network_history(height, function() {
+      return cb(true);
+    });
+  } else
+    return cb(false);
+}
+
 function check_show_sync_message(blocks_to_sync) {
   var retVal = false;
   var filePath = './tmp/show_sync_message.tmp';