Adding SentryClient
Fixed auth bug
Add fallback message generation, new serial for class
Merge tag 'acra-4.5.0RC2' into feature/sentry-sender

This updates SentrySender to use HttpRequest.setHeaders().

Conflicts:
	src/main/java/org/acra/collector/CrashReportDataFactory.java
	src/main/java/org/acra/util/HttpRequest.java