Fixed bug:  definitions of eq?, eqv?, equal?, =, functions were incorrect.

   NG:
     ev?    is Ruby's == method
     eqv?   is Ruby's === method
     equal? is Ruby's === method

   OK:
     eq?    is Ruby's equal? method
     eqv?   is Ruby's == method
     equal? is Ruby's == method
Update nendo.gemspec
Add Ignore file.