first commit
add intrusive splay tree
add order statistic tree and vector tree
add basic chain function
add replace feature for chain
add simple documents
add reverse feature for chain
add top feature for chain
add sum feature for chain
add max_element feature for chain
make replace, top and max_element features work together
make replace and sum work together
use perfect forwarding to make tree
remove lambda overloading
Move getNode to the last parameter, since getNode is likely use the default value.
use function overloading to dispatch
add member function node()
add max_sum feature for chain
fix #3: use initializer lists to insert value
fix #2