Impl 0.1.5 of swaybar_info

Impl 0.1.5 of swaybar_info

Implemented `--netdev_width=<width>` which sets the minimum width of the netdev
byte/KiB/MiB text displays.

Implemented `--netgraph_max_bytes=<bytes>` which displays a graph in text using
Unicode "Block Elements" symbols. The `<bytes>` argument determines the maximum
amount of bytes that will determine which block-character is printed on the
interval. The graph is always 10 characters wide, and the right side is the
most-recent side. Note that this always checks against the maximum of either
download or upload rates. For example, if `<bytes>` is set to 1024, and 128
bytes were downloaded and 512 bytes were uploaded in an interval, the "Lower
Half Block" Unicode symbol will be emitted (exactly half).

SwaybarObject was changed to use an `Option<String>` instead of an `Option<u16>`
for `min_width`.