ACCUMULO-2787 Tune max open file recommendation

Make the max files recommendation configurable to account for various
cluster sizes. Reduce the default from 64k to 32k because we shouldn't
need to compensate for running datanodes as the same user.
ACCUMULO-2884 Update source to remove TeX structure
Merge branch '1.6.1-SNAPSHOT'
ACCUMULO-2888 set the threads in the BatchWriterConfig
Merge branch '1.5.2-SNAPSHOT' into 1.6.1-SNAPSHOT
Merge branch '1.6.1-SNAPSHOT'