v1.0.4 - new CRAN release

• changed initial value in optim for variational variance (1 -> 0.1) in VE-step of PLN and PLNPCA
• fix sign in objective of VE_step for PLN with full covariance Issue #100
• add a scale argument compute_offset() to force the offsets (RLE, CSS, GMPR, Wrench) to be on the same scale as the counts, like TSS.
• fix nb_param for PLNLDA, which caused wrong BIC/ICL and erratic model selection
• fix minor issues #102, #103 plus some others
• fix package file documentation as suggested in r-lib/roxygen2#1491