Make the bibtex key mapping optional by additional argument in parser constructor
Removed comma after last key-value pair in bwriter.
Updated unit test for removing comma after last key-value pair.
Changed homogenise_keys to homogenise_fields.
Updated docs.
Doc fix.
add contributor for #28
Merge pull request #28 from faph/last_value_comma

Removed comma after last key-value pair in bwriter.
update for modif. in #29
update changelog ofr #28
Merge pull request #29 from faph/homogenise_keys

Make the bibtex key mapping optional by additional argument in parser
Merge remote-tracking branch 'upstream/master'

Conflicts:
	docs/source/tutorial.rst
Homogenise fields test fix.