Code clean up for mllib
Since getLong() and getInt() have side effect, get back parentheses, and remove an empty line
Indent two spaces
Merge remote-tracking branch 'upstream/master' into code-style
Added parentheses for that getDouble() also has side effect
remove "-XX:+UseCompressedStrings" option

remove "-XX:+UseCompressedStrings" option from tuning guide since jdk7 no longer supports this.
Clarify that Python 2.7 is only needed for MLlib
Merge pull request #444 from mateiz/py-version

Clarify that Python 2.7 is only needed for MLlib
Merge pull request #439 from CrazyJvm/master

SPARK-1024 Remove "-XX:+UseCompressedStrings" option from tuning guide

remove "-XX:+UseCompressedStrings" option from tuning guide since jdk7 no longer supports this.
Merge pull request #414 from soulmachine/code-style

Code clean up for mllib

* Removed unnecessary parentheses
* Removed unused imports
* Simplified `filter...size()` to `count ...`
* Removed obsoleted parameters' comments