Add license file LICENSE with LPGL license text copied from https://www.gnu.org/licenses/lgpl.html. Add license text to most of files of the project.

Add license text to all header files

Add license text to all c++ source files

Add license text to all C macro files

Converting file to UNIX format.

Add license text to all build system files

Add license text to all c source files

Rename file LICENCE to LICENSE. Change preamble in all files.