opentrack 2.3 release candidate 17 patchlevel 2

This is a breaking change release that begins to store configuration files in a single directory, Documents/opentrack-2.3 in user's home directory on Windows and the like. Copy your configs there so they're detected. There's no support for portable installations yet, provide feedback whether you need it.

• patchlevel 1 Some configuration bugs were fixed. Configuration shouldn't revert to settings from other configs now.
• patchlevel 2 interface won't lag anymore every few seconds.

Please report configuration file bugs in #179

• Configuration files rework. Also see the menu to the left of profile dropdown. File add and removal is detected automatically every three seconds.
• fix for FSUIPC for old FSX 2002/2004 potential memory leak. Report any crashes or other bugs.
• new RealSense tracker for Intel 3D cameras! @ph0b did the work.
• PT tracker shows point size and problems in detection on the screen.