Fix minor bugs to allow main file to work out of the box

[koyuul]

There are some small errors that need to be changed to use the main.py code out the box.

A list of errors that this addresses:

• a save_jpg vs saveJPG function naming error.
• a debug_information vs deubg_text_enabled parameter name error
• valid_5mp_resolutions being used under a 3mp dedicated function

[koyuul]

Added a commit with an example for multi-camera operation. Sorry, that should've been a separate branch commit but forgot to switch :P