[ContactsProvider] does not add own contact anymore

  * This fixes issue #47.
[UploadLogFile] improved logging of device
[ContactsProvider] make sure mContacts is never null inspired by Jan's review
[ContactsProvider] now clears cached contacts on error state inspired by Jan's review
Merge pull request #107 from simlar/own-contact-in-contactlist-pullrequest

Own contact in contactlist pullrequest