Release v4.4.16

The primary purpose of this release is to fix building on sparc64.
Additionally, there have been several code cleanups.  I would like the thank
Diane Bruce for inspiring the code cleanup and helping with pull requests;
also, a big thank-you to the Debian maintainer, Dave Hibberd (@Hibby), who
helped troubleshoot and provide guidance in solving the sparc64 build issue.

fix set but not used warnings

bugfix: only calculate the first frequency once

When rc_config.main_loop_start==true, the first frequency is calculated
twice:

Once when the program loads, and once when the loop starts.

This commit fixes that behavior.

clang: fix vectorization warning:

Update protoypes for functions with (void) that replaced ()

Release v4.4.15

glade: fix GTK crash related to menuitem icon

Release v4.4.14
This release fixes a hang when the frequency plots window is too small
for the number of plots being rendered.  Thanks to Tom DL1JBE who
reported the issue.

prevent hang when freq plot window is too small
show min/max values, now they do.

Release v4.4.13

This is a large bug-fix release and includes a few minor features and
documentation updates. Thank you to the many contributors who helped
with new features and bug fixes!