refactor lock and unlock in  recovery() of fileNodeManager [WIP]

Fix sonar bugs

# Conflicts:
#	iotdb-cli/src/main/java/org/apache/iotdb/cli/client/AbstractClient.java
#	iotdb-cli/src/main/java/org/apache/iotdb/cli/client/Client.java
#	iotdb-cli/src/main/java/org/apache/iotdb/cli/client/WinClient.java

add an initial committer: Kun Liu

add apache license for docs/*

* add configuration rpc_address for customize listen address

* add english doc

add partition start and end offset constraints when loading chunkGroupMetaData 

* add start and end offset of ChunkGroup in ChunkGroupMetaData

* check lsof command output for unsupported situation
* add warn log about unsupported OS for OpenFileNumUtil getting Pid

Add cache directories  for download jars and sonar plugin of Maven in  travis

* add Future for async flushing memtable, replace FlushStatus by Future

* using flushMemTable!=null to determine whehter a flushTask is running rather than using future.isDone()

* replace assertEquals with assertTrue or assertFalse; add logger.error for some exception; change the time unit of lastFlushTime as nanoTime

* [IOTDB-5]Deal with merge and other optimizations (#17)

add deletion function.

* fix IntervalFileNode

* fix a wrong branch in FileNodeManager

* some format refinements

* fix indent and equals() in Modification

* fix start JDBC service too slowly bug

* fix sonar before id 729

* revoke modifications for duplicated codes; polish according to reviews

* Update DeltaBinaryEncoder.java,  ChunkGroupFooter.java, TsFileDecodingException.java, BitmapEncoder.java, IoTDBQueryResultSet.java, IoTDBQueryResultSet.java, EncodingConfig.java for fixing Sonar tips.

* rename Compressor to ICompressor; rename UnCompressor to IUnCompressor

* Update Readme.md, replace old badge

* fix code smell: replace with METHOD_NOT_SUPPORTED_STRING

* fix sonar:

** delete redundant quotes

** remove redundant [ERROR]

* fix sonar problem in iotdb-cli/src/main/java/org/apache/iotdb/cli/tool/ImportCsv

* Update Readme.md, replace old badge

* fix sonar problem in auth package

* fix sonar problem in auth package

* fix sonar problem of iotdb concurrent package and conf package

* fix sonar problem in db conf and service

* delete reset lock exception in HashLock

* fix code problem in User.java

* fix sonar problem in IoTDBDescriptor

* fix sonar problem in conf and engine package

* add log error info for class BasicAuthorizer

* modify log info for BasicAuthorizer

* fix the log error format

* fix problem about logger and examine whether a string is empty

* logger -> LOGGER

* replace string.isEmpty() with "".equal()

optimize start-server.bat to adapt jdk version like '11+28' 

* add  to skip all UTs: maven integration-test -DskipUTS=true

* change the profile of skipUT_IoTDBTests to skipUT_IoTDB_Tests