[R] io "tell()" methods are inconsistently named and untested

[asfimport]

Looking in r/R/io.R, there is inconsistency as to whether the tell method of the various streams should be spelled "tell" or "Tell", and most are untested. Also, @pitrou asks, "is it necessary to redefine it [for all subclasses]? It should be inherited."

Reporter: Neal Richardson / @nealrichardson
Assignee: Neal Richardson / @nealrichardson

_{Note: This issue was originally created as ARROW-6449. Please see the migration documentation for further details.}

[asfimport]

Neal Richardson / @nealrichardson:
This is being done in ARROW-5505.