Add Page for User's Direct Reports

Update sample to show how to get a user's direct reports and filter
user's out of them
Add Group List View and Group Delete

New view lists all the groups similar to how the userlist view works. Only
action implemented for groups right now is delete.
Complete group examples

This finishes the last of the group samples for the graph library.
Specifically, create, details, edit, getting groups that this group is a
member of and getting a group's members.
Add Contact Graph Samples

Includes listing, viewing the details of the object and what groups
contacts are in. Additonally, a couple of small layout fixes are included
for groups and contacts
Adding comments/documentation to Groups and contacts
Add Roles features to the sample.

Only supporting listing roles, not adding users to a role. Also some other
UI cleanup included
Pull out configuration values into a static class

Moved the api version, graph resource id and tenant claim constants into a
static class to reduce code duplication and centralize their access.
Extract obtaining an access token to a separate class.

Reduces code duplication and shows the logic in one place.
Merge pull request #3 from Kapin/master

Update Samples for Graph Library 1.0 to add groups/contacts/roles.