Merge pull request #155 from SimonGoring/master

Added the bind method and merged @gavinsimpson's upstream pull #154
I think this is a mistake.
Big change that is probably going to fuck things up.

Merge remote-tracking branch 'upstream/master'

Conflicts:
	tests/testthat/test_neotoma.R
Merge branch 'master' of https://github.com/SimonGoring/neotoma
added .RData to the list of files to ignore.
Lower case changes to variable assignments in `chroncontrols` were not ported to `write_agefile`.