Revert benchmark helper regression. Use a #capture within a #benchmark
block. Breaks benchmark calls that return non-String values otherwise.

Revert "add benchmark helper that works in erb"

This reverts commit 904e544cc8f5846de7c31827bb5556c6a238c0de.

Conflicts:
	actionpack/lib/action_view/helpers.rb
	actionpack/lib/action_view/helpers/benchmark_helper.rb
	actionpack/test/template/benchmark_helper_test.rb
Rename :value option to :selected, in line with other select helpers
Add tests for time & datetime.
Add documentation.
test for ActiveModel::Conversion#to_partial_path and namespaced models
Merge pull request #8938 from colinbm/date_select_value

Rename :value to :selected for date_select, and add missing tests/docs
Merge pull request #8939 from senny/to_partial_path_test_to_prevent_regressions

test case for ActiveModel::Conversion#to_partial_path and namespaced models