Enhancements to Revel command

Reformat of code
Allow user to use a mix of command line arguments and flags
Enhance the import tool to detect missing packages in the modules side
Added test cases for all commands

utils/build_error.go

@@ -0,0 +1,45 @@
+package utils
+
+import (
+	"fmt"
+	"github.com/revel/cmd/logger"
+)
+
+type (
+	BuildError struct {
+		Stack   interface{}
+		Message string
+		Args    []interface{}
+	}
+)
+
+// Returns a new builed error
+func NewBuildError(message string, args ...interface{}) (b *BuildError) {
+	Logger.Info(message, args...)
+	b = &BuildError{}
+	b.Message = message
+	b.Args = args
+	b.Stack = logger.NewCallStack()
+	Logger.Info("Stack", "stack", b.Stack)
+	return b
+}
+
+// Returns a new BuildError if err is not nil
+func NewBuildIfError(err error, message string, args ...interface{}) (b error) {
+	if err != nil {
+		if berr, ok := err.(*BuildError); ok {
+			// This is already a build error so just append the args
+			berr.Args = append(berr.Args, args...)
+			return berr
+		} else {
+			args = append(args, "error", err.Error())
+			b = NewBuildError(message, args...)
+		}
+	}
+	return
+}
+
+// BuildError implements Error() string
+func (b *BuildError) Error() string {
+	return fmt.Sprint(b.Message, b.Args)
+}