[GTK] Simplify make-dist command line arguments
https://bugs.webkit.org/show_bug.cgi?id=134832

Reviewed by Martin Robinson.

.:
* Source/PlatformGTK.cmake: Use --version instead of
--tarball-root when running make-dist.py.

Tools:
Remove --tarball-root and -o command line options and add
--version, since the version can be used to build both, the
tarball root and the output filename. When the version it's not
provided, the pkg-config file is used to get the version. Also
change the default value of build-dir to the current directory,
since it's very common to call make-dist.py from the build dir.

* gtk/make-dist.py:
(get_tarball_root_and_output_filename_from_arguments):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@171297 268f45cc-cd09-0410-ab3c-d52691b4dbfc
[GTK] Documentation files are added twice to the tarball
https://bugs.webkit.org/show_bug.cgi?id=135115

Reviewed by Sergio Villar Senin.

* gtk/manifest.txt: Remove duplicated rules.

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@171298 268f45cc-cd09-0410-ab3c-d52691b4dbfc