uprobe_dup: new probe that duplicates an event to a second probe

[funman]

Usage example:

• FILE *f = fopen("log.txt", "w");
• assert(f);
• struct uprobe *uprobe_log = uprobe_stdio_alloc(NULL, f, loglevel);
• uprobe_stdio_set_color(uprobe_log, true);
• assert(uprobe_log != NULL);
• uprobe_main = uprobe_stdio_alloc(NULL, stderr, loglevel);
  assert(uprobe_main != NULL);
• uprobe_main = uprobe_dup_alloc(uprobe_main, uprobe_log, UPROBE_LOG);
• assert(uprobe_main != NULL);
• uprobe_release(uprobe_log);

To get both terminal output and file output (with colors)

[nto]

• Can you add a test case?
• Please fix the coding style so that function parameters are correctly aligned
• Commit title should be in imperative style and comply with the 50/72 Rule (eg: uprobe_dup: duplicate an event to a second probe)
• You may remove error handling from the example and use more helpful variable names (eg: file_output and term_output for each uprobe_stdio instance)