Small fix in abstract
Corrected fix error in introduction
Corrected double word in page 8.
Corrected page 8
Added vect in page 9
Corrected ponctuation in equation

Changed the implicit theorem with translation adding the hypothesis that A is invertible.
Changed bibliography programm
Bibliography reformated by kbibtex and added cfl condition reference.
Added remark and differentiation between Convection cfl and heat cfl.
Bibliography in toc.
Added new comparison plot for heat problem.

This include the graphic file (heatcomp.pdf).
This include the python source (comp.py).
This include pgf code for the marker (mark*.pgf).
Added comparatif figure + legend

Removed t=2s image because we have no comparison with other method and time step bigger than cfl.
Added sentence for the comparatif graph in heat equation solution.
Correction before extrapolation
Topology corrected extrapolation and interpolation.