#44 Fix warnings on non-checked returned results of asprintf(),

[TRINITON]

Fix build warnings on non-checked returned results of asprintf(), read(), and system().

rtctimer.c: warning: ignoring return value of 'read', declared with attribute warn_unused_result [-Wunused-result]
tvtimeconf.c warning: ignoring return value of 'asprintf', declared with attribute warn_unused_result [-Wunused-result]
tvtimeconf: warning: ignoring return value of 'asprintf', declared with attribute warn_unused_result [-Wunused-result]
tvtime.c: warning: ignoring return value of 'asprintf', declared with attribute warn_unused_result [-Wunused-result]
tvtime.c warning: ignoring return value of 'asprintf', declared with attribute warn_unused_result [-Wunused-result]
tvtime. warning: ignoring return value of 'asprintf', declared with attribute warn_unused_result [-Wunused-result]
commands.c: warning: ignoring return value of 'system', declared with attribute warn_unused_result [-Wunused-result]

[TRINITON]

Fix same build warnings