fix a bug: see 6b0cbc1bee671645d25ca4a5095b9b2b04b2c12d
implement patchwork --> loon (an l_compound) and loon (l_patchwork) --> patchwork. See d81d468ab7f229867f80e99f91d948b03ac73c63
Note that, not all designs in patchwork can be transformed to an l_compound object. Details see vignette ggplots --> loon plots
patchwork-->loon(anl_compound) andloon(l_patchwork) --> patchwork. See d81d468ab7f229867f80e99f91d948b03ac73c63 Note that, not all designs inpatchworkcan be transformed to anl_compoundobject. Details see vignetteggplots --> loon plots