Revert "bump to 1.6.1-dev"

This reverts commit 4989abc780b1fbae00fa3d3f34041734829063f9.
Revert "Doc: guide2 fix explanation of size_hint and attempt to add a little"

This reverts commit 994a0639d442142da2beca7c7824a51c05dc449a.
Revert "Revert "bump to 1.6.1-dev""

This reverts commit 3a7f3b9b8c7761e61ee61a89a86af1f5e525e45a.
Revert "Revert "Doc: guide2 fix explanation of size_hint and attempt to add a little""

This reverts commit 8a0d19e87e22b4989f2d7cd57b795120b66f9822.
Revert "Revert "Revert "bump to 1.6.1-dev"""

This reverts commit e7c2337d527777184dfbc1876fdeea2c554ebe9e.
Merge branch 'master' of http://github.com/kivy/kivy
doc: merge docs from old guide that were missing in new guide