Afloat Installer
Afloat is always on top solution on OSX, you can follow this post understand what does it do.
Always on top in MacOS Yosemite
Installation
open your terminal then copy and paste below:
curl https://raw.githubusercontent.com/rwu823/aflot/master/install.sh | sh
**input your password ** ●●●●●●
Reboot
Congratulation!! look at the Window menu
Key Binding
Test
Work fine on my OSX 10.10.x and 10.11, if any issues please post it.