* Yabroud gives government control from Damascus to Homs
* Rebels withdraw, lose vital cross-border supply line
* Battle intensifies to close border crossings to Lebanon
* Car bomb in Lebanon targets Hezbollah for Syria engagement
By Mariam Karouny and Stephen Kalin
BEIRUT, March 16 (Reuters) - Syrian forces backed by Hezbollah militants took full control of the town of Yabroud ...