Update copyrights for Collabora and General Electric Company

Looking at the diff statistics of the changes authored by me and landed
since 4.0.0 release points out these files as having major changes.
Update the copyright holders accordingly, as both clone mode and
touchscreen calibration related patches are copyright both Collabora and
GE.

I have kept the redundant "Copyright ©" form only to keep things
consistent, even when either the word or the mark would be enough.

Signed-off-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Acked-by: Ian Ray <ian.ray@ge.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>

compositor/main.c

@@ -1,9 +1,10 @@
 /*
  * Copyright © 2010-2011 Intel Corporation
  * Copyright © 2008-2011 Kristian Høgsberg
- * Copyright © 2012-2015 Collabora, Ltd.
+ * Copyright © 2012-2018 Collabora, Ltd.
  * Copyright © 2010-2011 Benjamin Franzke
  * Copyright © 2013 Jason Ekstrand
+ * Copyright © 2017, 2018 General Electric Company
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the

libweston/compositor-drm.c

@@ -1,6 +1,8 @@
 /*
  * Copyright © 2008-2011 Kristian Høgsberg
  * Copyright © 2011 Intel Corporation
+ * Copyright © 2017, 2018 Collabora, Ltd.
+ * Copyright © 2017, 2018 General Electric Company
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the

libweston/compositor.c

@@ -1,7 +1,8 @@
 /*
  * Copyright © 2010-2011 Intel Corporation
  * Copyright © 2008-2011 Kristian Høgsberg
- * Copyright © 2012-2015 Collabora, Ltd.
+ * Copyright © 2012-2018 Collabora, Ltd.
+ * Copyright © 2017, 2018 General Electric Company
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the

libweston/compositor.h

@@ -1,6 +1,7 @@
 /*
  * Copyright © 2008-2011 Kristian Høgsberg
- * Copyright © 2012 Collabora, Ltd.
+ * Copyright © 2012, 2017, 2018 Collabora, Ltd.
+ * Copyright © 2017, 2018 General Electric Company
  *
  * Permission is hereby granted, free of charge, to any person obtaining
  * a copy of this software and associated documentation files (the