Dmitry Valento

Fix selecting an exposure with mouse pressing.

Fix playing "beep" and "click" sound files on Windows.

Eliminate a possibility to set beep interval greater or equal to timelapse interval, because it leads to ommiting camera grabing.

Set using the ffmpeg as default encoder - now user won't be warned about unspecified encoder after new qStopMotion installation.

Show detailed ffmpeg's output only in verbose mode.

Build configuration for AppVeyour service has been done: file has been uploaded to repository (branch "develop"). Results of automatic building may be observed here (select job and then go to tab "Artifacts"): https://ci.appveyor.com/project/polovik/code

Fix crash, when try to press key "Space" or "Enter" when camera hasn't been turned on yet.

Add appveyor build configuration for x64