Implemented update stream sorting
Merge branch 'master' of https://github.com/ArnauPrat/ldbc_socialnet_bm

Conflicts:
	ldbc_socialnet_dbgen/src/main/java/ldbc/socialnet/dbgen/serializer/UpdateEventSerializer.java
Implemented sorted update streams
Merge branch 'master' of https://github.com/ldbc/ldbc_socialnet_bm