Moved DHT Node settings into a Dialog

Introduced DHTDialogFragment and refactored SettingsActivity to use it.
Merge branch 'master' of https://github.com/Astonex/Antox
Merge pull request #26 from GGreenwood/master

DHT Settings
Loading and Saving of a Tox data file
Auto delete Tox file on load as it throws an exception currently
Function wasn't compatible with API level 8
JTox was throwing an exception because username wasn't defined
Added double-locked checking and checks for ToxService running
Update README.md
Created a singleton for JTox
Merge remote-tracking branch 'antox/master'
Can now add friends and updated settings are sent to the network
Now gets friends list from tox rather than placeholders
General code cleanup
Read bytes from file instead of using string builder
Stop user opening a chat window with the "no friends" message
No need for using context in ToxDataFile.java
package name renamed
Simple style changes to settings activity
Permissions added in manifest, no need of context in ToxDataFile.java