* fixing a couple more warnings

* some more warnings removed
* preventing frame < 0

* defaulting to static_cast if the narrow_cast is not actually narrowing
* turn off shared libs

* fixing some warnings

* updating docs

* opening/closing video in separate thread

* coloration changes
* deselect on broken file
* removing some debug messages
* display average progress

* adding checkboxes to opening dialog
* renaming callbacks
* callback also on empty path
* hiding file selection when switching tabs
* video info for MP4s
* smaller fonts

* fixing issue #4
* adding Dropdown and Textfields to Opening page

* using averaging_method_t

* find sphinx, add docs target