Bug 1260651 part.34 Rename editor command classes and their file names r=mccr8

This patch renames editor command classes listed below:

* nsBaseEditorCommand -> mozilla::EditorCommandBase
* nsUndoCommand -> mozilla::UndoCommand
* nsRedoCommand -> mozilla::RedoCommand
* nsClearUndoCommand -> mozilla::ClearUndoCommand
* nsCutCommand -> mozilla::CutCommand
* nsCutOrDeleteCommand -> mozilla::CutOrDeleteCommand
* nsCopyCommand -> mozilla::CopyCommand
* nsCopyOrDeleteCommand -> mozilla::CopyOrDeleteCommand
* nsCopyAndCollapseToEndCommand -> mozilla::CopyAndCollapseToEndCommand
* nsPasteCommand -> mozilla::PasteCommand
* nsPasteTransferableCommand -> mozilla::PasteTransferableCommand
* nsSwitchTextDirectionCommand -> mozilla::SwitchTextDirectionCommand
* nsDeleteCommand -> mozilla::DeleteCommand
* nsSelectAllCommand -> mozilla::SelectAllCommand
* nsSelectionMoveCommands -> mozilla::SelectionMoveCommands
* nsInsertPlaintextCommand -> mozilla::InsertPlaintextCommand
* nsPasteQuotationCommand -> mozilla::PasteQuotationCommand

MozReview-Commit-ID: Lf6Lc39FpqM

--HG--
rename : editor/libeditor/nsEditorCommands.cpp => editor/libeditor/EditorCommands.cpp
rename : editor/libeditor/nsEditorCommands.h => editor/libeditor/EditorCommands.h

Author: masayuki-nakano