Clarification of which environment tests are run in
Added teamcity reporter

Added a reported for the TeamCity environment, allow tests to be
reported in TeamCity.
updated the news.md file

updated the news.md file to include the new TeamCityReporter.
fixed a big in SummaryReporter when label or info are vectors at the source by checking the expect_that args and stopping if they are wrong. Also now expect_that returns invisibly the result, useful for debugging
updated the doc of expect_that and NEWS.md
Enable devtools mode
Merge pull request #120 from kforner/master

fixed a bug in SummaryReporter when label or info are vectors at the source
Re-document and tweak news
Merge pull request #119 from windelinckx/master

Added teamcity reporter
Merge pull request #118 from wch/env-doc

Clarification of which environment tests are run in
Update docs and tweak news
Put reporters in own category of news
Export reporter accessors.
Closes #102
Add expect_null. Closes #78
Use consistent strategy for generating test env.
Part of fixing #111
Use globalenv as parent env for tests.
Closes #111
Add expectation for testing names.
Closes #79
Merge and squash. Closes #77
Tweak documentation & functionality of new expes
Upgrade to roxygen2 4.0.0