Add ability to specify the output path when using batch mode

[Andorbal]

Currently, the program will output the created files next to the input path, but this might not always be desirable (or possible, if files on a CD are used). The specified output path should be created, if it does not already exist.

Example:

KmlTimelineBuilder --inputPath c:\path\to\files --outputPath c:\path\to\created\files