Add default plugins, and install go plugin by default

runtime/plugins/go/go.lua

@@ -0,0 +1,49 @@
+function go_onSave()
+    if view.Buf.Filetype == "Go" then
+        if settings.GoImports then
+            go_goimports()
+        elseif settings.GoFmt then
+            go_gofmt()
+        end
+        go_golint()
+    end
+end
+
+function go_gofmt()
+    local handle = io.popen("gofmt -w " .. view.Buf.Path)
+    local result = handle:read("*a")
+    handle:close()
+    
+    view:ReOpen()
+end
+
+function go_golint()
+    local handle = io.popen("golint " .. view.Buf.Path)
+    local result = go_split(handle:read("*a"), ":")
+    handle:close()
+
+    local file = result[1]
+    local line = tonumber(result[2])
+    local col = tonumber(result[3])
+    local msg = result[4]
+
+    view:ReOpen()
+    view:GutterMessage(line, msg, 2)
+end
+
+function go_goimports()
+    local handle = io.popen("goimports -w " .. view.Buf.Path)
+    local result = go_split(handle:read("*a"), ":")
+    handle:close()
+
+    view:ReOpen()
+end
+
+function go_split(str, sep)
+   local result = {}
+   local regex = ("([^%s]+)"):format(sep)
+   for each in str:gmatch(regex) do
+      table.insert(result, each)
+   end
+   return result
+end