Fix: doc/examples VPATH build

Fixes #568

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cleanup: doc/examples makefile

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
tests: split in check, regtest and bench targets

Allow make check to run without requiring build machines to use hours of
CPU time.

make check: short unit tests
make regtest: long regression tests
make bench: long benchmarks

Fixes #611

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
README: document make check/regtest/bench

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Add missing tests/common/Makefile.am

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