date: add two methods in Date class

1) firstDate() returns the first Date in DateSet.
2) lastDate() returns the last Date in DateSet.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
docs: update README.mysql

1) add steps to import database.
2) add steps to install mysqldb in python.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
data: add 4 class methods

Added getOpen(), getClose(), getHighest(), getLowest().

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
test: add test subsystem

1) Add test subsystem
2) Move test.py to test

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_data.py

1) New test_data.py
2) Move the test for data.py from test.py to test_data.py
3) Pack the test into a function test_data()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_date.py

1) New test_date.py
2) Move the test for date.py from test.py to test_date.py
3) Pack the test into a function test_date()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_sim.py

1) New test_sim.py
2) Move the test for simulation.py from test.py to test_sim.py
3) Pack the test into a function test_sim()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_trade.py

1) New test_trade.py
2) Move the test for trade.py from test.py to test_trade.py
3) Pack the test into a function test_trade()

Signed-off-by: GuofengLiu <lgf612@sina.com>
test:test_mysql.py

1) Move the test for mysql out from test.py to test_mysql.py
2) Pack the test into a function test_mysql()
3) Currently we only have the test method for drop a table. Test_mysql should be defined a class which contain all of the methods for mysql test.

Signed-off-by: GuofengLiu <lgf612@sina.com>
test: change mode for tests

Added '+x' mode for tests

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
date: adjust arguments for two methods

Adjust arguments for better usage as below:
1) Change nextDate() to nextDate(date).
2) Change prevDate() to prevDate(date).

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
test: update date test

Updated date test because of the methods changed in Date module.

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
date: add two methods in Date class

Added isFirstDate() and isLastDate methonds in Date module

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>
test: add tests for date

Added tests for both isFirstDate() and isLastDate().

Signed-off-by: Zhengwang Ruan <ruan.zhengwang@gmail.com>