thrift added new api has_table, pymilvus should be update accordingly

1. change IndexType 1 to FLAT
2. fix find_vector_in_files ranges param bug

1. str of Milvus should contain server address
2. after set_client, the server address should be stored

1. Add new api search vector by files
2. fix search vectors return value bug

new milvus version add some new interface and change some original interface name,. It occured that pymilvus cannot run with newest milvus docker server

２００万向量，　ｎｑ＝１０００，　ｔｏｐｋ＝１００００
ｍｉｌｖｕｓ从接到请求到查询完成消耗大约１０秒，　而使用ｐｙｔｈｏｎ　ｓｄｋ则消耗了５０秒，有多余４０秒的消耗在ｓｄｋ这边

restore timeout api

This is a solution for issue #69

timeour causes lots of problems, need to remove

Add new IdnexType MIN_NSG

READEME.md should keep-up with newest sdk

1. should add utils.py module and optimize some dataclass
2. type of file_ids in searh_in_files api should be fixed up
3. Prepare after Prepare should not raise exceptions

MS-182

预期结果：参数检查，并返回参数错误信息

...
        query_ranges = [(get_current_day(), get_last_day(2))]
        status, result = connect.search_vectors(table, top_k, query_vecs, query_ranges=query_ranges)
>     assert not status.OK()
E       AssertionError: assert not True
E        +  where True = <bound method Status.OK of Status(code=0, message='Search Vectors successfully!')>()
E        +    where <bound method Status.OK of Status(code=0, message='Search Vectors successfully!')> = Status(code=0, message='Search Vectors successfully!').OK

should be QueryResult object

create table param dimension should be strict

• Status should be able to quick-check SUCCESS
• Status should be related to Thrift Exception
• TransportExceptions should be separated from ApplicationExceptions
• Log message should be more understandable

should be fixed up

• MS-165 default ip wrong
• MS-166 default ip wrong
• MS-167 default ip wrong
• MS-168 default ip wrong
• MS-169 default uri wrong
• MS-170 change repeatly connect error to status code

connected should return BOOL

Invalid IndexType should raise exception

IndexType should print it's name not confusing numbers

不可连接IP：123.0.0.1，需要设置超时

Logic of disconnection is wrong, should change connect_status after disconnected

1. example has a bug
2. readme should notify highest version of pymilvus for milvus-0.3.0

New interface has_table should be implemented in C++/Python SDK in release 0.3.0

This function will return if the table exists in Milvus DB by given table_name.

Even when there are too many vectors, these objects should be able to print out PART of the vectors, including:

1. TopKQueryResult
2. add_vectors return value ids

expected pirnt out:

ids = [1111111111111,
       1111111111112,
       ...
       1111111118888,
       1111111118889]

 TopKQueryResult=
 [ [QueryResult(id=000000001, distance=0.1234567678) ,
    ...
    QueryResult(id=000000001, distance=0.1234567678) ],

                           ...
                           ...
                           ...
                  
  [QueryResult(id=000000001, distance=0.1234567678) ,
    ...
   QueryResult(id=000000001, distance=0.1234567678) ] ]

RT

default to using thrift, can change to grpc by param

add new api build_index

_____ TestTable.test_create_wrong_table_name_null ________________________________________________________

self = <test_table.TestTable object at 0x7fb65c466eb8>, connect = Status(code=0, message='Connected')

def test_create_wrong_table_name_null(self, connect):
    '''
    target: test create table with no table_name
    method: create table with table_name: null
    expected: create status return not ok
    '''
    table_name = None
    param = {'table_name': table_name,
             'dimension': dim,
             'index_type': IndexType.FLAT,
             'store_raw_vector': False}
    status = connect.create_table(param)

  assert not status.OK()

E AssertionError: assert not True
E + where True = <bound method Status.OK of Status(code=0, message='Table None created!')>()
E + where <bound method Status.OK of Status(code=0, message='Table None created!')> = Status(code=0, message='Table None created!').OK

test_table.py:96: AssertionError

new indextype ivf-pq8 should be added

1.show hide Prepare and support old version

pymilvus currently doesn't support connect with DNS domain name.

When connecting celery server, param Index_type is converted to type of int, but type of IndexType is expected. It occured an error when type not match.