Some minor improvements

First of all thanks for the great project, it is really useful! I fixed some minor bugs related to parsing ... 

1.) The parser was crashing when there was a whitespace before the citationkey in a BibTeX record, like e.g. in 

@article{
       foo2012,
       title = "", 
       ... 

2.) There was a typo in the code which wrongly cut whitespaces from fields if the second character in a string was a whitespace. For instance this title 

"A new method for foo" 

would become 

"Anew method for foo" 

3.) I fixed an issue that led to an exception when files contain duplicate keys

4.) And finally I added another project type for the library which makes it portable also across Mono