scrpr

测试环境：CDNDrive v0.10 windows_amd64 上传文件：MiSans-Light.ttf BiliBiliDrive得到链接：`bdex://bdb86cae5eecf23d602f16a46314c22a7d346f87` ``` > ./CDNDrive download bdex://bdb86cae5eecf23d602f16a46314c22a7d346f87 panic: runtime error: slice bounds out of range [:101189545] with capacity 512 goroutine 1 [running]: CDNDrive/encoders.(*EncoderPNGBMP).DecodePNG(0x9e017c, {0x11d9e000, 0x299, 0x380}) CDNDrive/encoders/pngbmp.go:42...

fixes #26

When generating release file, identicial styles between multiple importing scripts will be duplicated.  Normally this does't cause any problem, but [AssFontSubset](https://github.com/tastysugar/AssFontSubset) crashes when it comes. I've submitted #25 to...