Update 1.1

The following update fixes issues #2 and #5 by doing the following:

• The two scripts download_stage1.py and download_stage2.py were merged into download.py with an optional command-line argument -n or --dry-run to signify running the query without downloading the files.
• The language command-line arguments are now optional, with the default coming from the OS setting. If the OS setting is not found properly, English (en) is the default, but this can still be overridden with the argument.

An additional minor change was made:

• The video quality command-line argument to download.py is now optional, and defaults to max.

The documentation has been updated to reflect this and the above changes, although not at the far-bottom examples section.