When hiding a ShowcaseView, release the bitmap to prevent out of memory issues
Update readme
Store shot state on touch hide

If hide on touch is enabled, the shot state should be stored when
hiding, just like in onClick.
Merge pull request #185 from Norkart/storeShotOnTouch

Store shot state on touch hide
Update ShowcaseView.java

calling hide() stores that this ShowCaseView has been shown.
Fix syntax errors on Gradle usage
Merge pull request #188 from juliendn/master

Update ShowcaseView.java