Switch from LGPL to FreeBSD license.

git-svn-id: http://svn.code.sf.net/p/adevs/code/trunk@235 153d293f-9360-418f-87de-c6d3afdd7922
Added note about thread safety of the crand class.

git-svn-id: http://svn.code.sf.net/p/adevs/code/trunk@236 153d293f-9360-418f-87de-c6d3afdd7922