Add command line option to pass a label command to the active profiling session

[JeremyMain]

When using GPUProfiler with a batch file, allow calling the GPUProfiler executable with a command line option to simply add a user defined label to the profile timeline during profiling.

This will be useful when using batch files to automate testing of different configurations.
Because it will be a simple command I could either create a small EXE to perform this or add this to the main application.

This is not an implementation sample, just a mockup to illustrate the feature.

[JeremyMain]

A global hotkey can be defined to "mark" points to be edited later to describe the operation or issue/event.
When loading a GPD file, during the inspection mode, labels can be added and edited later. These labels will be saved to the GPD file.

Current progress: