Modified calls to onShow(height) and onDismiss(height) so they both occur when the action is starting and they both provide an exact height in pixels instead of a maximum height. This helps in implementing floating action buttons movement with respect to the snackbar as specified in the material guidelines.

Also removed some unneeded calls to dpToPx().
Minor fix to text messages
Updated Android Gradle Plugin
mOffset is now retrieved with resources.getDimensionPixelOffset() instead of resources.getDimensionPixelSize()
@jrgonzalezg added as contributor
Merge remote-tracking branch 'upstream/master'

Conflicts:
	lib/src/main/java/com/nispok/snackbar/Snackbar.java
	lib/src/main/java/com/nispok/snackbar/listeners/EventListener.java
	sample/src/main/java/com/nispok/sample/snackbar/SnackbarSampleActivity.java
Listeners can now have full information about the process of showing / dismissing snackbars including duration of in/out animations

ActionClickListener now also provides the related snackbar instance

Some fixes to previous merge
Merge pull request #31 from jrgonzalezg/master

Modified callbacks so listeners receive full information of the process of showing / dimissing snackbars
reindent
code snippet update
Contributors section + reference to releases section
v2.5.0
Update README.md
Merge branch 'master' into develop