License header fixes Most of the source files had the wrong FSF address. Also reworded the first paragraph so that licensecheck's regexes actually pick up the version number. I made sure lttng.h and lttng-ctl.c advertise LGPL-2.1. Every other file touched in this patch was and remains under GPL2, please make sure this is correct. (Some files related to the RCU hashtable are under LGPL-2.1+, but their headers were already clean). (closes #155) Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Alexandre Montplaisir <alexandre.montplaisir@gmail.com> Signed-off-by: David Goulet <dgoulet@efficios.com>