Add license files mandated by (L)GPL.

Currently only qtbase includes the required LICENSE files, which
are referred to from the code headers. The same files should
be distributed as part of all the modules as well, so that the
(L)GPL licenses are adhered.

These files were wget:d from:

https://qt.gitorious.org/qt/qtbase/blobs/raw/stable/LGPL_EXCEPTION.txt
https://qt.gitorious.org/qt/qtbase/blobs/raw/stable/LICENSE.LGPL
https://qt.gitorious.org/qt/qtbase/blobs/raw/stable/LICENSE.GPL



Not sanitize-commit clean because those files aren't.

Change-Id: I9237ebc08e9a673dea9de81c5ddd348e1a93577e
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

LGPL_EXCEPTION.txt

+Digia Qt LGPL Exception version 1.1
+
+As an additional permission to the GNU Lesser General Public License version
+2.1, the object code form of a "work that uses the Library" may incorporate
+material from a header file that is part of the Library.  You may distribute
+such object code under terms of your choice, provided that:
+    (i)   the header files of the Library have not been modified; and 
+    (ii)  the incorporated material is limited to numerical parameters, data
+          structure layouts, accessors, macros, inline functions and
+          templates; and
+    (iii) you comply with the terms of Section 6 of the GNU Lesser General
+          Public License version 2.1.
+
+Moreover, you may apply this exception to a modified version of the Library,
+provided that such modification does not involve copying material from the
+Library into the modified Library's header files unless such material is
+limited to (i) numerical parameters; (ii) data structure layouts;
+(iii) accessors; and (iv) small macros, templates and inline functions of
+five lines or less in length.
+
+Furthermore, you are not required to apply this additional permission to a
+modified version of the Library.