DEVSIM under new open source license

The DEVSIM source code is now released under the Apache License, Version 2.0. It was previously under the LGPL 3.0. The license change is intended to promote adoption of the software and attract new contributors. A brief synopsis of the license is here.

The spirit of the Apache License is also more in line with the license terms packages that DEVSIM relies upon. More information about DEVSIM is available from https://www.devsim.org.