Added graphical simulator hepts
Added option -hepts to the compiler: this option formats the output of the simulation loop
to fit with hepts (currently working only on C target code). Typically, suppresses all
"decoration" output, like input or output names, and prints output on single lines.
Currently not implemented in hepts: array types.
Usage: to simulate the node Modulename.f:
heptc -target c -s f -hepts modulename.ept
gcc modulename_c/*.c -o ./f_sim
hepts -mod Modulename -node f -exec ./f_sim
