[biocswirl][dbg][test] Add R Linter

[lisancao]

[biocswirl][dbg][test] Add R Linter

Tasks

• Implement an R lintr that can validate BiocSwirl package code and omnitests

Resources

https://github.com/jimhester/lintr

Tag can be

biocswirl(related to course material)
biocterm (interface changes)
dev      (developers only)
file     (changes to file and folder structuring) 
rpkg     (r package/usethis and CRAN documentation changes)
feat     (new feature)
fix      (bug fix)
refactor (refactoring code)
style    (formatting, missing semi colons, etc; no code change)
doc      (changes to documentation)
test     (adding or refactoring tests; no production code change)
version  (version bump/new release; no production code change)
dbg      (Changes in debugging code/frameworks; no production code change)
license  (Edits regarding licensing; no production code change)
hack     (Temporary fix to make things move forward; please avoid it)
WIP      (Work In Progress; for intermediate commits to keep patches reasonably sized)