Added filter/concatenate to CMakeLists.txt
Modified the filter-chain.cc test to chain functions like so:
f1:R5->R1
f2:R1->R1
fchain = chain(f1, f2)
Doesn't work
Add missing include in bind.hh
Allow the use of a constant term in numeric quadratic formula
Merge pull request #36 from stanislas-brossette/master

Exhibit bug in filter/chain.hh
Fix filter-chain
Improve testing of numerical functions and chain
Fix numeric-quadratic-function
Optimize finite difference gradients
Optimize finite difference gradients further