Implement pagination on list of private+public repos of a user.

The paginated version of listRepositories() was 
missing at GHMyself: as side-effect of this bug
when requesting a paginated list of repositories
the ones privately owned by a user were not shown.

This was caused by the missing override of the 
listRepositories(final int pageSize) at GHMyself
that caused the GHPerson implementation to invoked.

The GHPerson version uses the /users/:org/repos?per_page=x
URL which *works fine* for organisations but unfortunately
*does not return* private repositories for users.

IMHO GitHub API are quite inconsistent form this 
point of view, but they are documented in this way
so that work (inconsistently) as designed.
Merge pull request #106 from lucamilanesio/master

Implement pagination on list of private+public repos of a user.