Rename launch commands
Rename launch commands

  BufferExplorer --> LustyBufferExplorer
  FilesystemExplorer --> LustyFilesystemExplorer
  FilesystemExplorerFromHere --> LustyFilesystemExplorerFromHere

Also:
- provide deprecation warnings for old names
- change *ExplorerCancel() and *ExplorerKeyPressed() from global
  to script-local functions.

treyhunner/dotfiles,treyhunner/dotfiles