whatNWISsites fixed, other bugs

Merge pull request #282 from wdwatkins/master

update version tag

NGWMN beta

Merge pull request #275 from ldecicco-USGS/master

update version

NWIS message

Merge pull request #265 from ldecicco-USGS/nwisChanges

Nwis changes

bug fix, beta message, retry

Merge pull request #259 from ldecicco-USGS/master

retry?

submitted to CRAN

Merge pull request #257 from wdwatkins/master

Fixed issue with new readr

2.5.10: Merge pull request #253 from wdwatkins/master

fixed additional importWaterML2 bugs, added tests

stats!

Merge pull request #243 from ldecicco-USGS/master

version

lt bug fix

Merge pull request #240 from wdwatkins/master

updated readNWISgwl description

bug fix

Merge pull request #231 from ldecicco-USGS/master

parse_number bug fix

head requests

Merge pull request #223 from ldecicco-USGS/master

Fix warning