Capitalize all NSLC info in returned fields for channel class

[alexhutko]

Returned N, S, L, C fields should be capitalized. In the search field, e.g. squac_client.v1_0_nslc_channels_list(network='uw'), upper should be accepted.

[{'class_name': 'channel',
'code': 'enz',
'created_at': datetime.datetime(2019, 10, 10, 20, 28, 7, 164189, tzinfo=tzutc()),
'description': None,
'elev': 1512.0,
'endtime': datetime.datetime(2599, 12, 31, 23, 59, 59, tzinfo=tzutc()),
'id': 1626,
'lat': 45.322262,
'loc': '--',
'lon': -121.650932,
'name': 'Mt Hood Meadows, OR CREST BB SMO',
'network': 'uw',
'sample_rate': 100.0,
'starttime': datetime.datetime(2018, 9, 18, 0, 0, tzinfo=tzutc()),
'station_code': 'hood',
'station_name': '',