(SERVER-4) Add memory check to Master Service

Add a memory check to the Master service's init function that,
when the /proc/meminfo file exists, parses it to get the total
amount of RAM on the system and fails if the total JVM heap
size is greater than 90% of RAM.
+1 to @camlow325 's suggestion, we should fix that now.

+1 to @dankreek 's suggestion too, but I think we should open up a jira for doing that In The Future.