During development one switches from GSM900 to GSM1800 and GSM850 to
GSM1900. This commit attempts to make this switch more easy.
GSM1800 and GSM1900 have overlapping ARFCNs. This means that the
mapping from bands to arfcn is not injective. Because of that I
removed the code to deduce the band from the ARFCN. This was done
in commit 8c3d807b3f. The auto-band
option allows to move between GSM900/GSM1800 and GSM850/GSM1900.
Add a simple testcase with these auto-band configurations.
