Fix minor typo in check_package documentation

Documentation on line 5 in `testthat/R/test-package.r` has 

> either \code{inst/tests}, or (better) \code{tests/testhat}.

Latter directory name should probably be `\code{tests/testthat}`.
removed the warning in case the srcref of the expect_call can not be found, e.g. for a bare expectation, as reported by Hadley
Merge pull request #96 from kforner/srcref_fix

removed the warning in case the srcref of the expect_call can not be fou...
added reporters ListReporter and MultiReported and their tests, new test for test_dir, fixed 2 bugs in source_dir(), factored out code from test_dir and test_file into .test_file, made all test function to invisibly return a summary df, changed parent environment of test evaluation environment to parent of globalenv()
Support relative paths in source_dir
Simplify relative path logic
implemented some hadley's reviews, added items to NEWS
new code review fixes: comment for parent.env(globalenv()), prettified dput data frame output
removed item test_dir tested from NEWS
added test for source_dir(), fixed a bug I introduced, and made sys.source2 to invisibly return the eval result, so that source_dir() returns it too, useful for testing
used proc.time() instead of Sys.time(), and output the three elapsed times: user, system and real
oups, forgot the test file for source_dir test
adapted tests and generated doc
Merge pull request #99 from jmcphers/master

Support relative paths in source_dir
Merge pull request #88 from jlehtoma/master

Fix minor typo in check_package documentation
merged from testthat hadley master
Merge pull request #106 from kforner/master

Return test summary report as a data frame
Is this a typo?
Merge pull request #107 from krlmlr/patch-1

Fix typo
merge from upstream