.emacs: Some trivial changes.

- Use henkan key to enable IME.
- Use muhenkan key to disable IME.
- Changed how to focus buffer-list.
- Open URL on remote host (needs server on remote host).
- Not truncate lines on markdown-mode.
- Changed key-bindings of org-mode's functions.
- Changed Pandoc's options used by markdown-mode.
- Limit org-agenda-files.
- Show org-mode's emphasis markers.
- Generate DOCX file when org-mode generates ODT file.
.bashrc: Export new variable 'REMOTE_HOST'.