Commit by Eriklintsev Ilya

1) Fixed SaveSolution and LoadSolution functions. Now they store all variables with maximum precision in binary format. Also .gitignore changed to ignore *.sol bindary solution files.

2) Added new Boundary condition ConstantVelocityBoundaryCondition. Analogue of NoSlip but with nonzero velocity on face.

3) Slight changes in main.cpp
Merge remote-tracking branch 'NewKidzTurbo/erik.fix.save.load.solution.convert.to.binary'