Update sample's build script

Update README to 2.1.3

Update to 2.0.3.

Bump version 1.8.3

New options: floatingLabelAlwaysShown and helperTextAlwaysShown.

Try to fix StaticLayout instantiate bug on some devices.

Sample update

added android:gravity attribute support for floating label.

Merge pull request rengwuxian#29 from hzsweers/master

Custom validation interface

Merge pull request rengwuxian#25 from hzsweers/master

Use IntDef for float label modes to have lint and better IDE autocomplete support