enrichR v3.0

• Updated enrichR.base.address
• Included additional enrichr sites including FlyEnrichr, WormEnrichr, YeastEnrichR and FishEnrichR (Thanks to Alexander Blume)
• Ability to generate a plot from the enrichment results (Thanks to I-Hsuan Lin) # enrichR v2.1
• Fixed bug by adding .onLoad hook to setup initial options
• Added bibliography directly and removed .bib as it was causing pandoc-citeproc problems with README.Rmd and vignette.
• Corrected spelling error in vignette # enrichR v2.0.
• Contains checks on enrichR website to ensure it is online.