Revert "[MainActivity] now starts CallingActivity and the CallingActivity then starts the call"

This reverts commit 09c745de5053b63cca81cab5f978663883ee5287.

* This fixes #44 and reopens #19.
[ContactsAdapter] now shows contacts even if SimlarStatus is ONGOING_CALL

 * This refixes #19.
[SimlarStatus] removed notification text change for status ONGOING_CALL

 * This fixes #42.
[RingtoneThread] now loads the ringtone in the thread
[UploadLogfile] now logs version and device
Merge pull request #45 from simlar/bugfix-and-little-improvements-pullrequest

Bugfix and little improvements pullrequest