Remove unnecessary casts

Remove unnecessary casts

xtend 2.7.x makes instanceof check an implicit cast for subsequent
variable usage, so these generate warnings. Also remove use of
deprecated types and speed up stringuilder usage by passing characters
instead of strings where possible.

Change-Id: I3131166a2fedf09743e6baf4159ba15357a37993
Signed-off-by: Robert Varga <rovarga@cisco.com>