run-clang-tidy-6.0.py -header-filter='.*' -checks='llvm-header-guard' -fix

[SMALL IMPROVEMENTS] When solving dual LP switch infeasible and unbounded return flags. In all equilibrium algorithms check whether the number of contacts is 0, in which case return appropriate result (typically infeasible). Improve test_static_equilibrium.

[IMPORTANT CHANGE] Take com as a 3d point rather than a 2d point (this should allow to consider cases in which gravityis not aligned with the z axis in the future).

Assume all contacts have same friction coefficient (change signature of setNewContacts method). Convert b0 (the minimum contact force generator coefficient) to e_max (the norm of the minimum force error that results in a violation of the friction cones).

Return the status of the LP solver rather than returning a boolean, so that the user can have a better understanding of what happened when the LP could not be solved.