blog: post about corrected Mini bootloader binary

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
less ambiguous names
README: explain that "staging" means staging.leaflabs.com

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>
new blog post
update blog phrasing
better forum link
fixes from violet
recent post: fix seeed link