[bugfix]
1.修复构建的时候报错的问题
2.修复travis-ci构建失败的问题

[Feature] 
1.升级electron版本
2.增加给PNGs每一帧修改延时的功能

Sparta 3.1 release!
[bugfix]
1.文件名带空格导致转换失败
2.PNGs转换WEBP没做压缩处理
3.设置循环次数无效
4.参数可设置为负值

[Feature] 
1.增加全局默认设置
2.增加多语言切换

[download]
微云下载地址：
mac : https://share.weiyun.com/e53b338a113fb12e17efef7f7115f2e8
linux: https://share.weiyun.com/b1e024e6c9d5cc03afa9e39d0062ac41
win32:https://share.weiyun.com/f1285b7bbb62d7ef4b95f1af54186ba4
win64:https://share.weiyun.com/07978e0e39483ffd0b5378e724efef1b

[Performance] Change PNG to APNG convertor to process each PNG in serial order to reduce CPU usage(important)
[Performance] Increase compression ratio for PNG to APNG lossless convertor with the new method
[Fix] Revert PNG to APNG converter refactor code for lossy conversion and back to previous method, which has a better compression ratio compared to the new method
[Fix] Fix wrong error tips for APNG to Animated WebP convertor

[Feature] PNG to APNG converter now supports lossless and lossy compression
[Performance] Refactor PNG to APNG converter and provide high compression ratio
[Performance] Remove apngopt dependence and reduce bundle size
[Experience] Support standard window keyboard shortcut on macOS
[Experience] Error tips for PNG to APNG converter now is more human readable
[Fix] Fix a issue that caused by detecting the wrong architecture on Windows

[Feature] Support Linux
[Performance] Update to apngasm 2.9.1
[Performance] Update to apngopt 1.4 (Linux 1.2)
[Performance] Update to pngout 20150319
[Performance] Update to pngquant 2.10.0 (Linux 2.5.0)
[Fix] Fix a bug that always show the tips the first time you launch if the current folder is empty

[Feature] Support APNG to Animted WebP converter
[Feature] Support i18n for English, Simplified Chinese and Traditional Chinese
[Performance] Update to nw.js 0.12.3
[Performance] Update to libwebp 0.6.0
[Performance] Update to apngopt 1.4
[Fix] Fix bug that apng convertor not check only 1 image and some tips issues
[Fix] Fix bug that imglossless convertor does not check JPEG and GIF images

[Feature] Add Windows setup and macOS binary
[Fix] Fix webp convertor bug
[Fix] Fix bug that unrecognize .JPG suffix files