v0.1.0

FastSpecSoG v0.1.0

Merged pull requests:

• revise interpolate_nu_single! (#1) (@ArrogantGao)
• using einsum! for FFCT interpolate (#2) (@ArrogantGao)
• added cheb interp for U_series (#3) (@ArrogantGao)
• added thin system energy solver by fat (#4) (@ArrogantGao)
• zeroth order term rewritten (#5) (@ArrogantGao)
• add changeable short range cutoff (#6) (@ArrogantGao)
• update show interaction (#7) (@ArrogantGao)