Merge pull request #40 from jca02266/add-examples

Add some examples and fix to work them
Merge pull request #41 from jca02266/add-examples

FIx testcase of Observable.generate
Workaround the test_parallel_wait, adjust the switching threads
Mark the ordering of flow of the test_parallel_wait
add a point of switching thread
Merge pull request #42 from jca02266/fix-test

Workaround for the test_parallel_wait test
Add Ruby 2.2.0 to .travis.yml
Merge pull request #43 from jca02266/fix-test

Add Ruby 2.2.0 to .travis.yml
Merge pull request #44 from jca02266/add-examples

Add some examples and implementation
Merge pull request #45 from jca02266/add-examples

Add some examples and implementation
Fix an output comment
Take out redundant parentheses after a method call
Make coding style rubyish
* use `unless` statement instead of `if` statement
* not to name an accessor method starting with `get`
Make an example run
Avoid failing sometimes in the test_parallel_wait

Control flow by thread queue instead of sleep
Merge pull request #47 from jca02266/fix-test

Avoid failing sometimes in the test_parallel_wait
Merge pull request #46 from minamimonji/refine-examples

Refine examples
Merge pull request #48 from jca02266/add-examples

Add some examples and implement Observable.while
Add an example of group_join
Implement Observable#group_join