refactor: link libvieter; remove cron code & daemon

This giant commit removes the old cron daemon & parser, replacing the
latter with a C implementation that will now be maintained in a separate
C library that gets developed independently. This commit lays the
groundwork for implementing features of Vieter in C where possible.

.gitignore

@@ -1,4 +1,4 @@
-*.c
+vieter.c
 /data/
 
 # Build artifacts