CB-5658 Delete stale snapshot of plugin docs
CB-5658 Add doc/index.md for Battery Status.
Fix up Markdown license to actually be in comments.
[CB-5658] Remove Apache license comment from README.md.

The LICENSE file is sufficient.
[CB-5658] Update license comment formatting of doc/index.md.
Fix typo in docs H2 -> H3
CB-5719 Updated version and RELEASENOTES.md for release 0.2.6
CB-5719 Incremented plugin version on dev branch.
Merge branch 'dev' of https://github.com/apache/cordova-plugin-battery-status.git into dev