Add #:include directive. Implement circular reference guarding and sanity checks.
Merge branch 'master' of https://github.com/kivy/kivy into kv_include

merge master before pull request
Correct example
Add option to force-include which first unloads the file and then reloads it. Check for proper extension and inclusion status before any disk access takes place. Update example.
Make the PID available to x and add the abillety to tell the window manager that the window should be above other windows by setting the env. variable KIVY_WINDOW_ABOVE
fix comment typo
doc: revisions to core/windows/__init__.py
doc: revisions to uix/relativelayout.py
doc: revisions to graphics/texture.pyx
doc: revisions to lang.py
doc: revisions to uix/scrollview.py
doc: Revisions to uix/stencilview.py
doc: revisiosn to properties.pyx
Merge pull request #1830 from jegger/x11_window_improvements

X11 window improvements
rst: fix white background + a possible issue with RstTerm/font_size. closes #1789
bump to 1.8.0
bump to 1.8.1-dev
Fix filechooser unicode test in py3.
Make vector test work in py3.
Merge pull request #1833 from matham/master

make py3 test succeed