Updated search to use new API; added lots of stuff from new API
Fixed issue with wrong date in search results
--amend
Added type field; simplified and unified construction of print messages when searching
Updated citation to new API
Changed bahaviour to request different bibliographic styles; added current allowed stylelist, which is used to be check the user's input
Removed format parameter, since everything is done via the style parameter now (using only x-bibliography in the request header)
Added publisher to avaiable search result options via parameter
Changed parser_doi to parser_cite
Added description for subparsers
Fix for unknown title field; Fix for show-publisher keyword
Added URL to available additional search parameters
Added hint to MIT license; added description for get_valid_styles method
Added check if DOI is valid and raise ValueError if not; allowed to create empty DOIs
Added default values for parameters in prepare_search_query; check the values for sort and order keywords
Added Testcases for DOI and request classes
Added test for file structure
Use dict.get method to define values if dict key not found; use defined values for unknown title, year and authors; updated format title methods in case of complete capitalized titles
Testcases for searchresult added
Included configparser for config file located at $HOMEDIR/.doi2bibtexrc; added sample config file