Added rectangle shape support

Merge pull request #28 from icechen1/master

Use rectangle shapes for highlight areas + other changes

build:gradle updated to 1.5.0

1.5.2

- Update gradle build as 1.5.0

Enhancement

enableIcon() is added.

MinSdkLevel is set to 14.

1.5

MinSdkVersion is set from 16 to 14.

OutOfMemory is fixed.

1.4

View is removed after dismissed.

PreferenceManages is updated.

You can reset all preferences.

Without retrolambda dependency.

1.2

Retrolambda dependency removed from materialintro library module.

Beta

1.0

Readme is updated.