Prevent sending too small amount

With Ğ1, the smallest amount that could be send is 0.01 because of the division by 100.

Done in 030e9a90.

changed milestone to %0.8.0

changed title from tx: prevent sending too small amount to Prevent sending too small amount

mentioned in issue #77 (closed)

changed the description

changed milestone to %0.7.0

assigned to @moul

mentioned in issue #193

changed the description

added CLI label

closed