Modify whitespace.

I've started using a different indent scheme in my code.
Use the same in this project.
Add René Nyffenegger's base64 functions.

I have slightly modified them, adding an encode function that takes a
string, adding copyright notices (including required notice that I
have modified René Nyffenegger's original), and changing the test to
assert rather than simply print its results.

This is part of #48.
Initial support for export and import via URL.

Add flags for exporting individual records to encrypted URL's and for
re-importing the resulting data.

Add first implementation of export function.  The import and regtest
will follow.

This is part of #48.