Police in the Central Bucks area have stepped up patrols following a series of burglaries, including one early Friday morning in Warrington, where a woman living near Route 611 and Bristol Road woke up to find a male intruder in her bedroom. She was frightened, but the man fled without harming her.  Police believe the same man may have committed other burglaries last week at three occupied homes and a gas station in Doylestown Township.  Cash and credit cards were stolen from the homes in the earlier burglaries, and cigarettes were stolen from the gas station.  Police are urging residents to lock their doors and report any suspicious activity.