Is a resistor required between VCC and Data for my temperature sensor?
The document with all your answers is the DS18B20 datasheet. Whenever you have questions about a part or interaction between multiple parts, the datasheet(s) should be the first thing you look at.

One of the more relevant statements from the datasheet:


  The control line requires a weak pullup resistor since all devices are linked to the bus
  via a 3-state or open-drain port (the DQ pin in the case of the DS18B20).


This pullup may also provide parasite power. Figure 1 shows a 4.7k resistor between V_PU and DQ.

Additionally, also from the datasheet:


  The 1-Wire bus requires an external pullup resistor of approximately 5kΩ; thus, the idle state for the 1-Wire bus is high.


That should answer your second question. To answer the first question, it's likely because it's a tutorial for using a TMP36 temperature sensor, which is completely different than a DS18B20. The TMP36 is an analog output temperature sensor, the DS18B20 is a digital temperature sensor that communicates via the 1-wire protocol (proprietary to Maxim), and consequently, there is really nothing in common between those two sensors. You will want to use a library that implements the 1-wire protocol to communicate with that sensor.