fix coefnames in table for an interaction

when the coef name for an interaction is reported using the coefnames function, it accidentally repeated the first variable in the interaction
relax typing on Associatives
remove export 'vector' and 'matrix'
Merge pull request #624 from ssirai/patch

remove export 'vector' and 'matrix'
Merge pull request #622 from catawbasam/master

relax typing on Associatives
Switch to Base.tty_size
Merge pull request #629 from JuliaStats/jmw/tty

Switch to Base.tty_size
Fix in-place associative methods so that they actually operate in-place

Previously empty! and insert! returned new DataFrames instead of
modifying their argument
Implement and export deleterows! with sane semantics

Fixes #595
Merge pull request #603 from timema/master

fix coefnames in table for an interaction
Add CSS class to DataFrame output
Merge pull request #636 from one-more-minute/patch-1

Add CSS class to DataFrame output
Merge pull request #634 from JuliaStats/sjk/associative

Fix in-place associative methods so that they actually operate in-place
Merge pull request #635 from JuliaStats/sjk/deleterows!

Implement and export deleterows! with sane semantics
Print errors for failed tests by default

Errors can optionally be silenced by passing -q
Add output to subsets examples.
Merge pull request #641 from astrieanna/add_output

Add output to subsets docs examples
tweak show(GroupedDataFrame) to match other show methods
Merge pull request #642 from JuliaStats/showgrouped

tweak show(GroupedDataFrame) to match other show methods
exported HOFs all do thunk

Some functions have a method whose final arg is a function.
The do block idiom doesn't work for those methods, so alternate methods
were added (exported functions with a single function arg only).