* Update WelcomeActivity.java
Now it starts welcome screen after not finishing the pager. Moved "Skip Tutorial" button here so it does not animate by swipe.
* Update activity_welcome.xml
Putting "Skip Tutorial" button here so that it does not animate by swipes.
* Update LoginActivity.java
Removing the set of "first run " flag from here. we set it after the buttons press or on WelcomeActivity's finish()
* Update welcome_do_upload.xml
removing "skip tut" button from here.
* Update welcome_dont_upload.xml
Removing "Skip Tutorial" button from here so that it does not animate by swipes.
* Update welcome_image_details.xml
Removing "Skip Tutorial" button from here so that it does not animate by swipes.
* Update welcome_wikipedia.xml
Removing "Skip Tutorial" button from here so that it does not animate by swipes.
* Update WelcomePagerAdapter.java
the "welcomyesButton" is removed from the child views in pager, so it is optional now.
* Add JavaDoc to WelcomeActivity.onBackPressed()
* Fix#2103: Remove welcomeYesButton from landscape layout
* Refactor WelcomePagerAdapter