use FiberError in fiber exception raise
refactor and use assert_raise in fiber test checking exception raise
make behavior of Fiber without block compatible with CRuby
should restore proc after rescue; close #1891
Fix literal asterisks in markdown
Fix typos in README
Add Enumerable#count comment
add tests for TrueClass

reorder and add tests for 15.2.5.1
avoid Dir.exist? that is not available in Ruby1.8
Merge pull request #1895 from stomar/typos

Fix typos in README.md and doc/compile/README.md
Merge pull request #1897 from suzukaze/add-enum-count-comment

Add Enumerable#count comment
Merge pull request #1898 from akuroda/pr_true_test

add tests for TrueClass