#368 Added markdown extra support

Added switch in settings to toggle markdown extra support.
Merge pull request #371 from eserkansozer/master

#370,#372, #373, #374, #376 Refactoring of SettingsViewModel class
Updated gitattributes
Fixed up issues with preview rendering after 1.7 upgrade
Merge pull request #378 from JakeGinnivan/FixedPreviewRendering

Fixed up issues with preview rendering after 1.7 upgrade
Merge branch 'master' of github.com:rcbdev/DownmarkerWPF
Fixed merge issue
Added publish to azure blob storage into build script
Removed turkish language as it is a really large dictionary file
Merge pull request #379 from JakeGinnivan/ClickOnceFinal

Click once publish to azure
Overwrite files when uploading to azure
Merge from upstream