add FeLINE2 and FeHEX8
add tests for FeLINE2 and FeHEX8
remove loops and reuse computed values
initialize with zero in ShapeMatrices constructor
merge coordinates mapping tests for different element types to one test
add tests for checking field specifications
merge tests for Fe types to one
test different fe types and different matrix types
fix clang compiling errors
add subdirectories under NumLib/Fem to CMake
use struct instead of template alias for gcc4.6
change ppa for petsc3.4.2
Merge pull request #383 from norihiro-w/add-fe-line-hex

Add finite element types LINE2 and HEX8
[AL] Forward additional args for local assembly.
[AL] Overloaded SerialExecutor::execute().

The overloaded version takes a third argument. This argument is used
needed properties in the local assembler.
[AL] Overloaded VectorMatrixAssembler::operator().

The overloaded version has a parameter for data needed by the local assembly process.
[AL] Add SimpleAssembler used for shape matrix initialization.

No local vectors/matrices and no modification of global vector/matrix.
[MGTL] Fix calculation of search length.

In case of aquidistant meshes the expression sum_of_sqr - (sum*sum)/edge_cnt can
get negative due to numerical calculation.  The root of a negative value is not
computable in real numbers.
[MGTL] Added class MeshNodesToPoints.

It is used for conversion of mesh nodes to geometric points required for
visualization.
[MGTL] Add assertion in MeshNodesAlongPolyline().