provides search/match service with PlaceholderPath

Replaced Scheduler::getCompletedFiles and Capture::checkSeqBoundary with corresponding PlaceholderPath functions to search for the number of captured files and the next sequence id.

Now, we can modify the format as we want and the captured file will be named correctly. However, the format is still hard coded in the source code.

I'll start working on creating a GUI to modify the format.