Merge branch 'develop' into backport

* Patch for file dialog on OSX

* Update CONTRIBUTORS.md

* 262 add wails shutdown method (#264)

* feat: support close in bridge mode

* feat: WailsShutdown callback

Now handles proper shutdown through:
  * runtime.Window.Close()
  * Killing the main window
  * Ctrl-C

* chore: version bump

cmd/version.go

@@ -1,4 +1,4 @@
 package cmd
 
 // Version - Wails version
-const Version = "v0.19.0-pre2"
+const Version = "v0.18.14-pre"

lib/renderer/webview/webview.go

@@ -13,7 +13,7 @@ package webview
 #cgo linux openbsd freebsd CFLAGS: -DWEBVIEW_GTK=1 -Wno-deprecated-declarations
 #cgo linux openbsd freebsd pkg-config: gtk+-3.0 webkit2gtk-4.0
 
-#cgo windows CFLAGS: -DWEBVIEW_WINAPI=1 -std=c99
+#cgo windows CFLAGS: -DWEBVIEW_WINAPI=1 -std=c99 -DUNICODE=1
 #cgo windows LDFLAGS: -lole32 -lcomctl32 -loleaut32 -luuid -lgdi32
 
 #cgo darwin CFLAGS: -DWEBVIEW_COCOA=1 -x objective-c