ACRA-5.1.2

Release Notes:
This is a pure bugfix release.

• Fixed #652 (StrictMode compatibility)
• Fixed #643 (Default string values were not set when the respective annotation was not present)

Acra-5.1.1

[Gradle Release Plugin] - creating tag:  'Acra-5.1.1'.

acra-5.1.0

[Gradle Release Plugin] - creating tag:  'acra-5.1.0'.

acra-5.0.0

Update README.md