Fixed connectionSize Limit

[AlexStanglEmerson]

T_O_Length is a UInt16, but when adding it and the t_o_headerOffset variables together to get the connectionSize, it was typecast to a byte. When working with a device that returns 496 bytes, an implicit connection could not be established due to this. The conversion was changed to a UInt16 to allow for all 9 bits.

I think issue #19 may be related to this.