Uses garbage free read-method on Reader for CSV reading

i.e. the method accepting a char[]. The read-method accepting a CharBuffer
is implemented wastefully in Reader, and should therefore be avoided. This
means that a new interface has been introduced, of which javadoc explains
the situation as well.
Merge pull request #3476 from tinwelint/2.2-less-gc-thread-ahead

Uses garbage free read-method on Reader for CSV reading