Subconvert

* ADD: Enabled menu bar subtitles editing (+undo/redo)
* ADD: "Save as..." opens a file in new tab to which subs are saved.
* ADD: Inserting and removing subtitles.
* ADD: Jumping to the start of highlighted sub
* FIX: Fixed not showing errors on "save all"
* FIX: Show a message box when there's an error on SPF saving
* FIX: Update "subtitles menu" on file list selection change
* FIX: Strip subtitles from whitespaces
* FIX: Fixed loading autoInputEncoding SPF flag
* FIX: Fixed displaying timestamp for some kind of movies
* FIX: Added missing window icon
* MOD: Change SubtitleProperties format: pickle -> JSON
* MOD: Changed forward/rewind shortucts to ctrl+right, ctrl+left

* ADD: spinbox on subtitle time edit
* FIX: installing Subconvert icons
* FIX: missing icons
* MOD: FPS value from pfile will be used when there's no FPS specified

* ADD: complete redesign of GUI which has a lot of cool features:
* subtitle editing
* undo/redo
* batch or single file works
* reencoding of subtitle file
* side panel
* ADD: introduced Subtitle Property Files
* ADD: introduced output file syntax ("%f" substitution)
* FIX: correct internationalization (moved *.po files + use of ngettext)
* MOD: HUGE code refactoring
* MOD: changed hand made install script to autotools
* MOD: migrate Subconvert to Python 3
* MOD: subconvert by default spawns GUI. Use '-c' to access commandline
interface

* ADD: "-g" option to SubConvert CLI version
* ADD: 32: added icon for the GUI file list which indicates a status of a job
for that file
* FIX: 42: MPL2 error with one-digit time indicators
* FIX: A lot of (hopefully all) filename encoding issues are now fixed
* FIX: Two untranslated strings are now translatable
* FIX: SubOptParser gettext issues
* FIX: Help text unification
* FIX: 35: silence MPlayer error
* FIX: 33: omit Byte Order Mark in UTF8 files
* FIX: proper arguments parsing in GUI
* MOD: Rewritten command line options
* MOD: 40: GUI: change the way that logging is handled. Most significant
change are individual logs for each file on the list (available after
double-click on that file)

* ADD: Polish translation
* ADD: Auto detection of more movie formats (both GUI and CLI)
* ADD: New install script
* FIX: SubConvert detects both upper case and lower case movie extensions
* FIX: with '-v' option, SubConvert will not require any additional parameters
and will simply try to get FPS from a given file
* FIX: 25: changed string concat method in MicroDVD
* FIX: Tests work again
* FIX: Crash when input string contained non-ascii characters
* FIX: SubConvert will now try to auto detect locale path
* MOD: 'Auto FPS' checkbox is now checked on GUI start
* RMV: Combo box from GUI with an output sub extension

* ADD: Unit tests
* ADD: option to specify output file(s) encoding
* ADD: MPL2 format support
* FIX: HUGE code refactoring
* FIX: ugly converting error (which doubled first subtitle and removed the
last one)
* FIX: incorrect SubViewer miliseconds converting
* FIX: SubRip skipping last sub when no new line at the EOF (now Generic
Parser forces parsing a section at the EOF)
* FIX: smart skipping of incorrect empty lines
* RMV: custom updater