A version that can be merged with master
build system added.
add “缺省值”
delete .settings
support limit ;pushing down condition is ok ,but filter is not supported
f
add build system and change environment variable.
add third party package.
little change for beauty
add create projection while create table
add mysql connection pool and libeasy rpm to thirdparty.
add O0 compile optimization.
blocked in connection 2.
blocked in connection 2, and we need sovle the simple return result.
repair bug in create table by adding first column named row_id
conf相对路径问题.
rename the binary executed file.
every column support null or not null when create table
Merge remote branch 'yukai-0708/master' into alpha

Conflicts:
	Config.cpp
load successfully