Fix: snapshot should fail if no successful snapshot is taken

Fixes #606, #608

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: remove calibrate syscall option from code

Fixes #586

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: typo in configure.ac for version check

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: add missing short filter option in help

Fixes #587

Signed-off-by: David Goulet <dgoulet@efficios.com>
Fix: improve error message when UST support is disabled

Fixes #583

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>