[RJ-Server] Corrected code style

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>
[RJ-Server] Added rni method to create SYMSXP from STRSXP directly
[RJ-Server] Enhanced rni method to get variable in enviroment using SYMSXP
[RJ-Server] Fixed crash if a binding in an environments throws an error

Signed-off-by: Stephan Wahlbrink <sw@wahlbrink.eu>