Initial Commit
Updated GridFunction::NLinearValue()
Test test1 now includes GridFunction::NLinearValue() call
Test test1 now uses 5.8, 5.8, 5.8 instead of 5.6, 5.6, 5.6
replace all size_type with size_t
Create NDVectorArray base virtual class and NDVector base class
Update GridFunction to inherit from NDVector
Update Makefile: test1 now depens on GridFunction.hpp and NDVectorArray.hpp
replace size_type with size_t in test1.cpp
fix type in test1.cpp
fix typos, add this-> to function calls (fix bugs introduced by NDVector base class of GridFunction)