v1.5.3

What's changed:

• Implement audio drive for digital modes (Issue #186)

• Remember which S-meter face the operator picked, in [ui] rather than in a radio's view, so it survives a restart (issue #185)
• Implement SmartSDR connection based on how AetherSDR is doing it (Issue #184)
• Report FreeDV from whichever radio is in RADE, and take the tracking filter out of a Blog V4's HF path (issue #182)
• Teach the Icom LAN backend the IC-7760, so its 689-bin scope and its own menu numbering work over the network (issue #183)
• Give packet radio a connected-mode terminal, so an operator can reach a node or a BBS and not only watch UI frames go past (issue #159)
• Read an ADIF file that is not UTF-8 instead of dropping the whole import, so a log with Cyrillic or accented fields loads (issue #163)
• Read RDS text through the standard's own character table, so ä, ö and å arrive as letters instead of dots (issue #173)
• Keep the packet bit clock's fractional remainder, so an SDR's channel rate transmits at the right baud (issue #180)
• Let a direct-sampling RTL-SDR reach 17 m and 15 m in the ADC's second Nyquist zone (issue #179)
• Reorganize spectrum and waterfall settings
• Load an FDM-S1/S2's FPGA at open, which is what makes it stream at all (issue #178)
• Keep the panadapter together while a drag carries the window across the band (issue #177)
• Split the digital TX audio level into FM deviation and sideband drive
• Make skimmers focus on visible spectrum
• Fix jittery remote tuning
• Fix remote spectrum scrolling being slower than the timestamps
• Let a station's radios sign in one at a time, and stop a busy server costing the remembered password (issue #176)