rtransparent 0.2.5

A vignette has been added to help illustrate how to use the package.

rtransparent 0.2

rt_coi now searches for Conflicts of interest statements within text files.
rt_fund now searches for Funding statements within text files.
rt_register now searches for Registration statements within text files.
rt_all now searches for many indicators within text files.
rt_read_pdf now converts PDF files into TXT using poppler.

rtransparent 0.1

Initial commit of functions to analyze PMC XML files for indicators.