Fix hasShowcaseView() method in case there is no target set

Without this patch, the method will return true if the target is set to Target.NONE. In
this case showcaseX and showcaseY is set to -1 and hasNoTarget is set to true. Since
the method is used by the TextDrawer class, the text bounds were incorrect without
a target.
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
Adding the capability to include MediaRouteButton as an ActionViewTarget
Fixed error java.lang.OutOfMemoryError

Fixed error java.lang.OutOfMemoryError when the function updateBitmap() was called.
Update for latest gradle versions
Merge remote-tracking branch 'origin/master'
Update readme for v5
Merge pull request #202 from naddaf/master

Adding the capability to include MediaRouteButton as an ActionViewTarget
Merge pull request #204 from tato469/patch-1

Fixed error java.lang.OutOfMemoryError
Merge pull request #177 from ejonny/master

Fix hasShowcaseView() method in case there is no target set
Merge remote-tracking branch 'origin/master'
Update gradle for 5.1.0-SNAPSHOT
Fixes #33 and helps with localisation
Improve javadoc target

Links to both the Java javadoc and the Android javadoc