Merge pull request beeware#1242 from paulproteus/scroll-to-row-android

Implement DetailedList.scroll_to_row on Android

Bumped version number for v0.3.0.dev26 development.

Merge pull request beeware#1110 from SamSchott/meta-example

An example overview making it easy run multiple examples

Merge pull request beeware#1088 from saroad2/add_textinput_validator

Add TextInput validator

Revert to organization level templates.

Bumped version number for v0.3.0.dev22 development.

Fix release script handling of demo pinning.

Fixed packaging of toga-demo.

Bumped version number for v0.3.0.dev19 development.

Bumped version number for v0.3.0.dev18 release.