Added Oscilloscope & PID skeleton.
PID: Draft server part (parameters) implementation.
Scope+PID: GUI: Cleaned generator elements, added PID elements & bindings.
PID: Pid module initialization added.
PID: FPGA memory map structure fixed.
PID: Fixed signedness of PID parameters (Sp, Kp, Ki, Kd).
PID: Reset & turn off all PIDs at application init & exit.
PID: Added integrator reset controls to GUI. I reset now does not return to 0 by itself.
FRA: Added initial draft of Frequency Response Analyzer.
FRA: Removed unused parameters.
FRA: Removed unused params/elements from GUI. Global file descriptors made local.
FRA: Removed obsolete fft signal.
FRA: Coding style. File descriptors local.
FRA: GUI re-styled to current Red Pitaya apps look & feel.
Scope+PID: Increased timeouts to accommodate AUTO for slow input signals (<= 2Hz).
OS: Added static/manual network configuration option.
Fixed jumping Freq & Period numerics in Measure panel.
Scope*: X range limited from 20 ns to 20 s. Freq/Period displayed with 4 digits.
OS: Added avahi daemon for mDNS support.
Scope+PID: prevent buttons to remain grayed out

Additionally: disable user input for both the slider and Trigger level
input field in case of Trigger mode other than Normal and in case of
Trigger source = External.