yield current running example to it/example and before/after hooks
rdoc tweaks for deprecated example method and block argument
rename to instance_exec_with_rescue and remove unused override of instance_eval
doc tweaks [ci skip]
add examples for deprecated Example#example and Example#running_example
use double quotes (consistency w/in the file)
yield the example to the block passed to let or subject
Merge pull request #666 from rspec/yield-example

yield current running example to it/example and before/after hooks