Many initial updates related to changes to fishR

[droglenc]

These are changes primarily related to the new fishR webpagge. The most important changes are ...

• Changed DHO e-mail address (in DESCRIPTION and in all author fields of the documentation). Partially address #86.
• Updated links in fishR(), FSA(), and README.md. Partially address #86.
• Updated all links to Introductory Fisheries Analyses with R book.
• Added links to CSV files for all data sets. This addresses #96.
• Changed theme in _pkgdown.yml to match that of FSAdata and more closely match fishR.
• Removed most recent dates from NEWS file as pkgdown picks up the CRAN release date to add.