merge from master
total rewrite the logic
revise the interface
totally rewriting
add Eclipse formatter for team dev work
fix interface a little
实现了基本的浮点矩阵操作
merge
Add Sparse Vector implementation
the first version of the engine interface
实现稀疏矩阵
orgnize imports
add more impls of SimEngine
most of SimEngine are done
add norm() and clone() method
merge guokr/develop
Merge pull request #16 from zmouren/develop

Develop
Totally rewrite the server code; restructure packages; still work in
progress
restructure test package
fix compilation error by comments