fix a  grammar mistake in docs

a small grammar mistake and should be "a device".

fix system memory check in iotdb-env.sh

update Travic.yaml to suppress mvn log

remove win-oracleJDK11 and Linux-OracleJDK11 on travis-ci temporary.

* add sync docu

* modify sync docu according to pr review

* multi-directories avoid using disk without space

* fix that MManager is incorrectly recovered when system reboots

* clean overflow files when storage group is deleted

Fix a doc bug of QuickStart.md

The word colomn should be column.

simplify Path construction, which improves 17% write speed

[IOTDB-107]fix missing wal log node after recovery

* organize properties

* add time unit

* fix mistakes in doc

* use a more elegant way to return results of Authorization queries like 'LIST USERS'

* fix tests

* improve client display

* fix a test in windows

* fix client display

* keep stack trace when logging or throwing an Exception

* fix jira issue 100

* remove useless code

* modify logic: add params in ReadOnlyTsFile's query function not in constructor

* remove loadMode; update the calculation of remaining time ranges

* fix sonar

* refactor iotdb code for cluster

* delete useless code

* fix issues according to pr reviews

* fix issues according to pr reviews

* delete useless code in MGraph

* delete useless map in Metadata

* delete useless map in Metadata

* update

* update

* fix some issues

* update combineMetadatas() in Metadata

* update combineMetadatas() in Metadata

* remove closeClusterService

* print debug information about the start and end position of chunkgroupMetadata

fix a bug in TsFile-Spark-Connector

* add logical part for global time filters from partition problem

* Update README.md, doc, dependency version pom, .travis.yml

* modify scala version to 2.11.8 and restrict java version to 8, change scalatest version from 2.12 to 2.1

* refactor query resource count

* format code

* fix a bug

* remove lock