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.
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
Improve javadoc target

The title of the javadoc is now more human-readable
Update copyright