Tweak to topfeatures documentation.
down to just 2 warnings on the CHECK now...
New version 0.5.1 which passes all checks, includes a few minor bug fixes (see NOTES).

Moved twitter.R into R_NEEDFIXING until it can be restored to working status.
Merged dev branch to master, for 0.5.1

Merge branch 'dev'

Conflicts:
	DESCRIPTION
	quanteda.pdf