Update version to 1.5.1

Allow setting gain to 0 dB in constructor

Update version to 1.5.0

Set total center frequency of the chain instead of center frequency of RF element

Use getSampleRateRange instead of listSampleRates (if available)

Make label optional in detected devices

Fix compatibility with Python 3.4

Update version to 1.4.0

Add get_gain_range() and get_frequency_range() methods

Remove force_bandwidth option from LimeSDR hardware quirks

Use getBandwidthRange instead of listBandwidths (listBandwidths is deprecated)

Add list_stream_args() method; allow setting buffer_size and stream_args in constructor; allow setting stream_timeout in start_stream()

Remove RTL-SDR and SDRplay hardware quirks (fixed upstream)

Allow listing, getting and setting SoapySDR device settings

Update version to 1.3.0