Fixes #151 #505 

* Added isLandscape data.

* Updated docs with isLandscape addition.

* Updated docs.

In #466 the export of the main module was changed to use default export.
Change the typescript declaration to use default export, too.

* Support android version code under 24

* Revert "Support android version code under 24"

This reverts commit e1899138b95bc8f71aab1877c2c2627ecab5e1c4.

* Change default compile sdk version to 24

* Support deprecated locale access on Android

* Add change log

This commit will clarify in the README that both "iOS" and "iPhone OS" are possible return values from calling getSystemName when running on an iOS device. "iOS" being reported on most iOS 10+ devices and "iPhone OS" reported on iOS 9 and less and some iOS 10 devices.