improve read_hivproj_output()

[jeffeaton]

• correct 5 year age groups (0-5, 5-10, ...) --> (0-4, 5-9, ...)
• add names to dimnames(specres).
• convert 5 year outputs to 3 dimensional arrays. E.g. newinf.m &newinf.f matrices become newinf array.
• add a melt.specres(specres, ...) method to convert specres outputs to long format using as.data.frame.table(). Optional pars argument should allow to specify which parameters to include and exclude = FALSE/TRUE to indicate whether to exclude pars.