Merge pull request #184 from crowding/fastrbind-rebase

rbind.fill performance and consistency
Silently drop NULLs in rbind.fill().
Closes #138
Mute note about "no visible binding for d" by creating an unused variable with this name
New parameter .id for ldply() to specify name of index column (default: .id); fixes # 140; fixes # 107
New parameter .id for rdply() to specify name of index column (default: .n); fixes # 142
update Rd files
Generate .id column as factor in ldply(); fixes # 137
add NEWS
Merge pull request #187 from krlmlr/mute-l_ply-note

Mute note about "no visible binding for d" by creating an unused variable with this name
Merge pull request #188 from krlmlr/fix/140-142-id-137-column-as-factor

Enhancements for *dply
fixes # 158 by evaluating the .expr parameter and calling it one time less if it actually is an expression and not a function
update NEWS
fix tests to account for .n being a factor in result of rdply
Merge pull request #189 from krlmlr/fix/158-rply-expr

r?ply issues
Convert NEWS to md
Fix linebreak
Roxygenize to set C sorting of family-generated documentation
Don't use a factor for ID column if .id parameter is not set in ldply() and rdply()

This is to ensure backward compatibility with the many packages that depend on plyr, e.g., ggplot2
Roxygenize
Merge pull request #195 from krlmlr/id-na

Don't use a factor for ID column if .id parameter is not set in ldply() and rdply()