Ham tests.
Add new excite methods for the three-site ham case.
3-site ham excitations now working in top. triv. case.
Fix non trivial excitations for 3 site ham.
Add new eps_ function needed for three site ham excitations.
Merge branch 'three_site_h' of github.com:amilsted/evoMPS into three_site_h
Tweak and document restore_RCF and bond-dimension truncation.
Fix uniform case for D=1.
Add excitations testing to uniform ising ham test script.
Split out bond-dimension truncation into separate method. Restore canonical form after truncating.
Move truncation to separate method. Do it during update() by default.
Fix take_step for ham_sites != 2.
Improve previous commit.
Add save_memory option to take_step().
Remove redundant parameter and add a comment.
Add expect_3s() for three-site operators.