Log Message:
sfeed_curses: Update to 1.0

Changes:
1.0
---
* Makefile: switch to use CPPFLAGS -D_DEFAULT_SOURCE preventing warning
  messages on some systems.
* sfeed_curses:
   * Fix (false-positive) compiler warnings with gcc 10.2+ and -Wall -O2.
   * Check if capname is NULL for tparm(), noticed on netbsd-curses.
   * Add [ and ] keybind to open the next visible feed in the pane while
     keeping the current pane selection, thanks to adc for the feature
     suggestion.
   * Exit early on read errors and show a clear error message in these cases.
   * Improve consistency of line counting (on an invalid file).
   * Theme: add a version of the mono theme (mono_highlight) which highlights
     the active panel.
   * minicurses.h: fix parameter type for tparm() (long not int).
* sfeed_content:
   * Content view optimizations.
   * Show any other content-type than "html" as plain-text (because Atom
     allows base64-encoded embedded content).
   * Allow multiple file parameters as arguments.
* sfeed_markread:
   * Make sure to use proper permissions when copying the merged temporary
     file.
   * For the unread items: create the file if it does not exist.
   * Allow to set the url as a parameter or as an env variable.
   * Use "-" instead of /dev/stdin which is slightly more portable.
* Code-style improvements.
* Documentation improvements: add examples, fix typos, etc.