Remove some more unnecessary files.

Removes the Spanish (or something) readme file, the same info (license only) is in the English readme file. Removes the IntelliJ config files (they shouldn't be version controlled, IntelliJ can generate them from the Maven POM).
Update README.md with information from readme.txt.
Add .gitignore to ignore IDEA files (and Eclipse/Maven/OS files)
Update client SDK dependency to 10.0.0 and reformat pom.xml.
Reformat source and remove unused classes.
 Remove some code warnings.