(HOW TO) Change All Of Status Bar Icons On Lollipop (Battery, Signal, Etc).

Required Items

1. Apktool
2. Systemui.apk
3. Some Images (png files)

Steps

1. Extract (De-compile) your Systemui.apk
2. Go to res/drawable.
3. In this folder, you will see the XML files for any icons on your status bar.
4. Delete those XML file. For example, if you wanna change the signal icon, just delete that "stat_sys_signal_0, stat_sys_signal_0_fully" etc... 
5. Put that .png images for replacing xml files that you was deleted before on any drawable folder that fits your resolution (mine is drawable-hdpi). Ex: if you delete that stat_sys_signal_0 on your drawable folder, then you have to put that stat_sys_signal_0.png to replace it. 
6. After you finish replacing all XML files with .png images, recompile it.
7. Don't forget to sign it and push into your system.
8. Done

Important Note:  Remember that XML file name before you deleting it.