[BUGFIX] In-memory columnar storage bug fixes

Fixed several bugs of in-memory columnar storage to make `HiveInMemoryCompatibilitySuite` pass.

@rxin @marmbrus It is reasonable to include `HiveInMemoryCompatibilitySuite` in this PR, but I didn't, since it significantly increases test execution time. What do you think?

**UPDATE** `HiveCompatibilitySuite` has been made to cache tables in memory. `HiveInMemoryCompatibilitySuite` was removed.

Author: Cheng Lian <lian.cs.zju@gmail.com>
Author: Michael Armbrust <michael@databricks.com>

Closes #374 from liancheng/inMemBugFix and squashes the following commits:

6ad6d9b [Cheng Lian] Merged HiveCompatibilitySuite and HiveInMemoryCompatibilitySuite
5bdbfe7 [Cheng Lian] Revert 882c538 & 8426ddc, which introduced regression
882c538 [Cheng Lian] Remove attributes field from InMemoryColumnarTableScan
32cc9ce [Cheng Lian] Code style cleanup
99382bf [Cheng Lian] Enable compression by default
4390bcc [Cheng Lian] Report error for any Throwable in HiveComparisonTest
d1df4fd [Michael Armbrust] Remove test tables that might always get created anyway?
ab9e807 [Michael Armbrust] Fix the logged console version of failed test cases to use the new syntax.
1965123 [Michael Armbrust] Don't use coalesce for gathering all data to a single partition, as it does not work correctly with mutable rows.
e36cdd0 [Michael Armbrust] Spelling.
2d0e168 [Michael Armbrust] Run Hive tests in-memory too.
6360723 [Cheng Lian] Made PreInsertionCasts support SparkLogicalPlan and InMemoryColumnarTableScan
c9b0f6f [Cheng Lian] Let InsertIntoTable support InMemoryColumnarTableScan
9c8fc40 [Cheng Lian] Disable compression by default
e619995 [Cheng Lian] Bug fix: incorrect byte order in CompressionScheme.columnHeaderSize
8426ddc [Cheng Lian] Bug fix: InMemoryColumnarTableScan should cache columns specified by the attributes argument
036cd09 [Cheng Lian] Clean up unused imports
44591a5 [Cheng Lian] Bug fix: NullableColumnAccessor.hasNext must take nulls into account
052bf41 [Cheng Lian] Bug fix: should only gather compressibility info for non-null values
95b3301 [Cheng Lian] Fixed bugs in IntegralDelta
HOTFIX: Use file name and not paths for excludes
SPARK-1488. Resolve scalac feature warnings during build

For your consideration: scalac currently notes a number of feature warnings during compilation:

```
[warn] there were 65 feature warning(s); re-run with -feature for details
```

Warnings are like:

```
[warn] /Users/srowen/Documents/spark/core/src/main/scala/org/apache/spark/SparkContext.scala:1261: implicit conversion method rddToPairRDDFunctions should be enabled
[warn] by making the implicit value scala.language.implicitConversions visible.
[warn] This can be achieved by adding the import clause 'import scala.language.implicitConversions'
[warn] or by setting the compiler option -language:implicitConversions.
[warn] See the Scala docs for value scala.language.implicitConversions for a discussion
[warn] why the feature should be explicitly enabled.
[warn]   implicit def rddToPairRDDFunctions[K: ClassTag, V: ClassTag](rdd: RDD[(K, V)]) =
[warn]                ^
```

scalac is suggesting that it's just best practice to explicitly enable certain language features by importing them where used.

This PR simply adds the imports it suggests (and squashes one other Java warning along the way). This leaves just deprecation warnings in the build.

Author: Sean Owen <sowen@cloudera.com>

Closes #404 from srowen/SPARK-1488 and squashes the following commits:

8598980 [Sean Owen] Quiet scalac warnings about language features by explicitly importing language features.
39bc831 [Sean Owen] Enable -feature in scalac to emit language feature warnings