Make it easier to read and to write floats and one-byte bools

[sakuraehikaru]

If a characteristic is simply of a common type such as an integer, float, or string, and if there's no need for other handling, we shouldn't require developers to create structs for those.

[sakuraehikaru]

We can do it for strings (check the format of the standard string used by characteristic like the serial number), but Int should already be handled.

Floats and Bools (might need to double check its format in BLE) as well.