Bibtex import translator is now called instead and other imrovements

* Bibtex import translator is now called internally (this deals with all kind of character encoding problems as well as spacing problems)
* every entry types is handled now by just checking if the class "entry" is contained in the list of all classes
* detectWeb is (for creating the right symbols) updated
* there are also person-pages, i.e. lists of publication from an author (added in detectWeb as multiple)
* cases where DBLP uses crossref fields and links for example an inproceeding to the proceeding (second entry) is dealt and the information of it is used as well
* replace BibTeX field "ee" (DBLP) which is normally named "url"
* some fixes and code improvements according to the comments by aurimasv and adam3smith
* asynchronity with import calls are handled: import on second data (if any) is called before the import on first data, such that the additional information from the second data item can be added in the corresponding fields with the first data
* url with doi are handeled better
* Improving code and test cases