Expose enrg_md_steps option in mrdna and enrgmd scripts and in mrdna.simulate.multiresolution_simulation(); thanks to Elija Feigl for the suggestion

Fix multiple issues related to strand generation, also reduce timestep to 100fs if coarse_local_twist==True

Fixed two small bugs, one involving use of is for string comparison, the other involving an incorrect function call when a restraint is added to the system with only one argument

Removed os.sync() lines prior to running arbd/oxDNA simulations because they can hang indefinitely; needs testing

 https://gitlab.engr.illinois.edu/tbgl/tools/arbdmodel

https://gitlab.engr.illinois.edu/tbgl/tools/arbdmodel

https://gitlab.engr.illinois.edu/tbgl/tools/arbdmodel

Improved orientation potentials at junctions when local_twist is enabled; now dihedrals are more local and work in more situations

Added routines for inserting and removing DNA; made it so atomic simulation doesn't resize model dimensions

Fixed multiple issues; 3-prime ends of nucleotides now terminate correctly; strands not cleared unless atoms exist; strands regenerated with atomic model; cadnano models initialized with more correct azimuthal angle