Major changes in this release:

Release 1.7.7

Specific changes:

• Issue 202 Initial support for ECMA Script 6 "method definitions".
• Issue 201 Make sure that all native Error instances can be converted
  to JSON.
• Issue 184 Fix compile encoding errors.
• Issue 178 Support build using Gradle (build using Ant is still
  supported but will be removed in a future release.)
• Issue 176 Add ScriptRuntime.throwCustomError to make it easier
  to re-throw Java exceptions
• Issue 166 Support many ES6 additions to the Math class.
• Issue 165 Support many ES6 additions to the Number class.
• Issue 163 Support ES6 additions to the String class.

Thanks to everyone who contributed!