Interactive mode for multiple files

[MihaiUdrea]

We could extend the interactive mode support to multiple files/solution/project.

Limitations/Chanlanges:

• clang-query requests the searched files in command line its length limit is easily reached
• multiple processes must be orchestrated
• file change refresh

Proposal:

• Leverage CurentDir, Relative Paths and ShortFileNames to maximize the no of files a clang-query instance searches in
• start each clang-query proc in its optimum working dir (we could start them in batches to balance the system load, and that will also give us a progress indicator)
• send the query to all the processes
• gater all the results
• at the next query, verify which files are newer than the process that handles it, and with all these files start a new clang-query process. Also ignore subsequent results for those files from previous query instance, but leave the old query process alive to handle the other files.