ebuild variable references fixed
ebuild's cleaned up and slimmed down
stable branch of btsync updated from 1.3.94 to 1.3.105
btsync binary install path corrected to Gentoo standard: /opt/
systemd service unit CPU & I/O priority lowered to idle
systemd service units reference corrected btsync binary path
OpenRC/init.d files tied up and reference corrected binary path
Manifest file rebuilt
