Kernel#open should correctly handle objects that responds to to_open
Kernel#singleton_methods should return a unique list of methods
Fix Encoding#compatible? failing rubyspecs.
Improved code formatting:

- Removed unused import,
- Added some whitespaces where missing,
- Removed a pair of curly braces for a simple if.
Merge pull request #706 from atambo/kernel_open_to_open

Kernel#open should correctly handle objects that responds to to_open
Merge pull request #707 from atambo/kernel_singleton_methods_uniq

Kernel#singleton_methods should return a unique list of methods
Merge pull request #708 from tychobrailleur/encoding_fix

Fix failing rubyspecs for Encoding#compatible?
Get EINPROGRESSWaitWritable from proper location. Fixes JRUBY-7161
Merge remote-tracking branch 'github/master'
Enable more tests for Socket stuff.
Exception#== should return true if the two exceptions inherit from Exception but have different classes
Complex#/ with a Numeric which responds to #real? with false should coerce the passed argument to Complex and divide the resulting elements
Make .java_class work properly for "real" ifc impls. Fixes #709.
Only call dataGetStruct once.
Merge pull request #711 from atambo/exception_equals_different_classes

Exception#== should return true if the two exceptions inherit from Exception but have different classes
Merge pull request #712 from atambo/complex_divide_non_real

Complex#/ with a Numeric which responds to #real? with false should coerce the passed argument to Complex and divide the resulting elements