ACCUMULO-3030 allow scanners to be interrupted
ACCUMULO-3180 Better test naming and some extra functionality to SlowIterator
Merge branch '1.5' into 1.6

Conflicts:
	test/src/main/java/org/apache/accumulo/test/functional/SlowIterator.java
Merge branch '1.6'
ACCUMULO-3085 Fix log message
Merge branch '1.5' into 1.6

Conflicts:
	server/tserver/src/main/java/org/apache/accumulo/tserver/Tablet.java
Merge branch '1.6'
ACCUMULO-3187 Up the default memory for MAC for ExamplesIT

Was seeing some OOMEs. Give the JVM a little more headroom.
Merge branch '1.6'
ACCUMULO-3135 Fix javadoc misuse of link
Merge branch '1.5' into 1.6
ACCUMULO-3190 Fix deprecation warning
Merge branch '1.6'
ACCUMULO-3182 Gracefully handles incomplete/missing WAL headers.

Need to still create an empty MapFile before recovery, otherwise
MultiReader will throw a BufferUnderflowException. Pulled the "finished"
and "failed" WAL recovery markers into an enum for easier use. Also
adds an IT that verifies the fix works.
ACCUMULO-3182 An extra test that partially writes the WAL header.
ACCUMULO-3182 Move some convenience methods into SortedLogState to clean up the calling code.
ACCUMULO-3182 Lift the try/catch around all of the readHeader WAL method.

Use offline/online instead of restarting the tserver in the IT. Caught an NPE on
closing an empty/malformed WAL. Ensure that the GC doesn't delete our
WAL before the metadata entry references it.