Fix for Windows Phone 8 template.

Added MediaElement to the WP8 template so now it works.
Merge branch 'develop' of https://github.com/mono/MonoGame into develop
Adds the default constructor for TouchCollection.

Without this constructor the TouchCollection class, since is a struct
and don't need to be instantiated, can throw some exceptions when you
call, for example, the Count method. This assures full XNA
compatibility.
Revert "Adds the default constructor for TouchCollection."

This reverts commit 0dd53002c61196a5d8deb33c4d7a47a6c1114b50.
Revert "Fix for Windows Phone 8 template."

This reverts commit 56dd0d7b6d60f8f2353c7e781751fadd79faea57.
Adds the default constructor for TouchCollection.

Without this constructor the TouchCollection class, since is a struct
and don't need to be instantiated, can throw some exceptions when you
call, for example, the Count method. This assures full XNA
compatibility.
Error checking for _collection.
Merge pull request #1675 from azchohfi/touchcollectionfix2

Adds the default constructor for TouchCollection.