Argument to reduce output apk size (optimize)

[faizul726]

Related: #148

In MT Manager (an Android app) it's possible to use the Optimize APK function which basically compress stuff in apk. I often need to use the option to reduce the size of libs. It's pretty slow on phones.

So, my suggestion is to add an optional argument that optimizes output apk size. Like --optimize.

That way I don't have to manually optimize after merging an apks file.

[REAndroid]

Check this commit:ea49069

[faizul726]

Thank you.