BEAST 2.2.1 release

BEAUti some bug fixes involved in linking/cloning + some cosmetic changes

Better error reporting:
- in BEAUti, estimate of relative substitution rate for single partition only caused BEAST to hang
- check correct java version (8) is used
- package manager warns when there is no internet connection

Improved NEXUS Standard datatype support

TreeAnnotator improved sampled ancestor support

CLI script now sensitive to JAVA_HOME environment variable

DensiTree updated to v2.2.1