Add some :commands for basic usages

python3/vimspector/debug_session.py

@@ -403,6 +403,9 @@ class DebugSession( object ):
   def ShowOutput( self, category ):
     self._outputView.ShowOutput( category )
 
+  def GetOutputBuffers( self ):
+    return self._outputView.GetCategories()
+
   def _SetUpUI( self ):
     vim.command( 'tabnew' )
     self._uiTab = vim.current.tabpage

python3/vimspector/output.py

@@ -206,3 +206,6 @@ class OutputView( object ):
                    tab_buffer.index,
                    utils.Escape( category ),
                    '*' if tab_buffer.flag else '' ) )
+
+  def GetCategories( self ):
+    return [ category for category in self._buffers.keys() ]