Update codegangsta/cli

To fix #122.
IsSet() doesn't return true even when env variables are set.

vendor/github.com/codegangsta/cli/category.go

@@ -0,0 +1,44 @@
+package cli
+
+// CommandCategories is a slice of *CommandCategory.
+type CommandCategories []*CommandCategory
+
+// CommandCategory is a category containing commands.
+type CommandCategory struct {
+	Name     string
+	Commands Commands
+}
+
+func (c CommandCategories) Less(i, j int) bool {
+	return c[i].Name < c[j].Name
+}
+
+func (c CommandCategories) Len() int {
+	return len(c)
+}
+
+func (c CommandCategories) Swap(i, j int) {
+	c[i], c[j] = c[j], c[i]
+}
+
+// AddCommand adds a command to a category.
+func (c CommandCategories) AddCommand(category string, command Command) CommandCategories {
+	for _, commandCategory := range c {
+		if commandCategory.Name == category {
+			commandCategory.Commands = append(commandCategory.Commands, command)
+			return c
+		}
+	}
+	return append(c, &CommandCategory{Name: category, Commands: []Command{command}})
+}
+
+// VisibleCommands returns a slice of the Commands with Hidden=false
+func (c *CommandCategory) VisibleCommands() []Command {
+	ret := []Command{}
+	for _, command := range c.Commands {
+		if !command.Hidden {
+			ret = append(ret, command)
+		}
+	}
+	return ret
+}