I've added an interface to JavaUtils to do byte conversion and added hooks within Utils.scala to handle conversion within Spark code (like for time strings). I've added matching tests for size conversion, and then updated all deprecated configs and documentation as per SPARK-5933.

Author: Ilya Ganelin <ilya.ganelin@capitalone.com>

Closes #5574 from ilganeli/SPARK-5932 and squashes the following commits:

11f6999 [Ilya Ganelin] Nit fixes
49a8720 [Ilya Ganelin] Whitespace fix
2ab886b [Ilya Ganelin] Scala style
fc85733 [Ilya Ganelin] Got rid of floating point math
852a407 [Ilya Ganelin] [SPARK-5932] Added much improved overflow handling. Can now handle sizes up to Long.MAX_VALUE Petabytes instead of being capped at Long.MAX_VALUE Bytes
9ee779c [Ilya Ganelin] Simplified fraction matches
22413b1 [Ilya Ganelin] Made MAX private
3dfae96 [Ilya Ganelin] Fixed some nits. Added automatic conversion of old paramter for kryoserializer.mb to new values.
e428049 [Ilya Ganelin] resolving merge conflict
8b43748 [Ilya Ganelin] Fixed error in pattern matching for doubles
84a2581 [Ilya Ganelin] Added smoother handling of fractional values for size parameters. This now throws an exception and added a warning for old spark.kryoserializer.buffer
d3d09b6 [Ilya Ganelin] [SPARK-5932] Fixing error in KryoSerializer
fe286b4 [Ilya Ganelin] Resolved merge conflict
c7803cd [Ilya Ganelin] Empty lines
54b78b4 [Ilya Ganelin] Simplified byteUnit class
69e2f20 [Ilya Ganelin] Updates to code
f32bc01 [Ilya Ganelin] [SPARK-5932] Fixed error in API in SparkConf.scala where Kb conversion wasn't being done properly (was Mb). Added test cases for both timeUnit and ByteUnit conversion
f15f209 [Ilya Ganelin] Fixed conversion of kryo buffer size
0f4443e [Ilya Ganelin]     Merge remote-tracking branch 'upstream/master' into SPARK-5932
35a7fa7 [Ilya Ganelin] Minor formatting
928469e [Ilya Ganelin] [SPARK-5932] Converted some longs to ints
5d29f90 [Ilya Ganelin] [SPARK-5932] Finished documentation updates
7a6c847 [Ilya Ganelin] [SPARK-5932] Updated spark.shuffle.file.buffer
afc9a38 [Ilya Ganelin] [SPARK-5932] Updated spark.broadcast.blockSize and spark.storage.memoryMapThreshold
ae7e9f6 [Ilya Ganelin] [SPARK-5932] Updated spark.io.compression.snappy.block.size
2d15681 [Ilya Ganelin] [SPARK-5932] Updated spark.executor.logs.rolling.size.maxBytes
1fbd435 [Ilya Ganelin] [SPARK-5932] Updated spark.broadcast.blockSize
eba4de6 [Ilya Ganelin] [SPARK-5932] Updated spark.shuffle.file.buffer.kb
b809a78 [Ilya Ganelin] [SPARK-5932] Updated spark.kryoserializer.buffer.max
0cdff35 [Ilya Ganelin] [SPARK-5932] Updated to use bibibytes in method names. Updated spark.kryoserializer.buffer.mb and spark.reducer.maxMbInFlight
475370a [Ilya Ganelin] [SPARK-5932] Simplified ByteUnit code, switched to using longs. Updated docs to clarify that we use kibi, mebi etc instead of kilo, mega
851d691 [Ilya Ganelin] [SPARK-5932] Updated memoryStringToMb to use new interfaces
a9f4fcf [Ilya Ganelin] [SPARK-5932] Added unit tests for unit conversion
747393a [Ilya Ganelin] [SPARK-5932] Added unit tests for ByteString conversion
09ea450 [Ilya Ganelin] [SPARK-5932] Added byte string conversion to Jav utils
5390fd9 [Ilya Ganelin] Merge remote-tracking branch 'upstream/master' into SPARK-5932
db9a963 [Ilya Ganelin] Closing second spark context
1dc0444 [Ilya Ganelin] Added ref equality check
8c884fa [Ilya Ganelin] Made getOrCreate synchronized
cb0c6b7 [Ilya Ganelin] Doc updates and code cleanup
270cfe3 [Ilya Ganelin] [SPARK-6703] Documentation fixes
15e8dea [Ilya Ganelin] Updated comments and added MiMa Exclude
0e1567c [Ilya Ganelin] Got rid of unecessary option for AtomicReference
dfec4da [Ilya Ganelin] Changed activeContext to AtomicReference
733ec9f [Ilya Ganelin] Fixed some bugs in test code
8be2f83 [Ilya Ganelin] Replaced match with if
e92caf7 [Ilya Ganelin] [SPARK-6703] Added test to ensure that getOrCreate both allows creation, retrieval, and a second context if desired
a99032f [Ilya Ganelin] Spacing fix
d7a06b8 [Ilya Ganelin] Updated SparkConf class to add getOrCreate method. Started test suite implementation