Added an empty gerbil_keys.properties

refers to #29
Created a better solution for the gerbil_keys.properties problem. The start.sh creates an empty file if it doesn't exist. This prevents git from trying to upload the file if it is added to the .gitignore file.
Sorry, in my last commit some lines of the start.sh were commented out. I Fixed this.
Fixed an error inisde the MatchingFactory causing problems with C2W experiments. Refers to issue #30.
Added a better error handling to the NERDAnnotatorConfig.
Checked the NERD annotator and made some minor changes. Moved the key property into the gerbilkeys.properties file. However, I couldn't test the annotator without a key.
Checked the FOX annotator. Created a simple testing main class for it. Cleaned up some classes. Removed the time measurement because it isn't used in our version.
include needed libraries for using the nerd4java client
Merge branch 'master' of github.com:AKSW/gerbil
add boilerplate license to the NERD Annotator
Tested the NERD adapter and made some minor changes on its classes (refers to #16).
Merge branch 'master' into wat-inclusion
Merged the master into this branch. Added a simple test class. Made some minor changes in the mapping classes.