2.6.49

Fixed

• Use bundled file for browser field (#3904) (20d66cf, @luciorubeens)
• Reduce download block size when getting no block (#3905) (e223287, @air1one)
• Ping ports using head (#3905) (db226bd, @air1one)
• Stricter rate limit for getBlocks (#3905) (df7a3aa, @air1one)
• Allow to discard possibly invalid txs from pool (#3905) (0450ee8, @air1one)
• Check sig length vs R and S length (#3905) (1b0863c, @air1one)
• Check that R and S is positive (#3905) (0783ec0, @air1one)