Merge pull request #557 from kostya/index

Array#index
# merge master
untag some specs
Merge pull request #552 from kostya/minmax2

Enumerable, Array#minmax
small style fixes
fix for subscript assignemnt with no args
fix for augmented subscript assignment with no values
These specs now pass!
make tags more precise, add Fixnum#~
added subscripting to fixnums
untag another spec (expose Bignum class)
Added Fixnum#>>
added a bunch of constants
more passing tests
a bunch of trivial integer methods
this passes
more passing specs
Make send splat be more efficient with large array splats
moving flatten to internal module
Merge remote-tracking branch 'origin/master' into flatten