fixed issue of dialogMessage not used and shown

updated all sdks.

updated sdk versions

removed NumberEditTextPreference, as EditTextPreference can handle it…

… anyway.

fixed duplicate ripple effect on Android 6 and above.

updated versions of all stuff...

Merge pull request AndroidDeveloperLB#21 from jemshit/master

Almost fixed ripple effect issue on android 6 when pressing preferences items. See this: AndroidDeveloperLB#19
Also, for some reason, now it sometimes show the ripple in the middle.

Update README.md

Update build.gradle

Merge branch 'master' of https://github.com/AndroidDeveloperLB/Materi…

…alPreferenceLibrary

Update README.md

Merge pull request AndroidDeveloperLB#5 from jitpack-io/master

Added android maven plugin