add note about using cwd with files
fixed typo in cwd example
fixed typo
emphasize cwd option
Merge pull request #60 from dylancwood/update_cwd_docs

add note about using cwd with files
allow deletion of tags
Merge pull request #69 from pghalliday/deletetag

allow deletion of tags
Merge remote-tracking branch 'origin/master' into v0.2.x