RFXtrx433E FW update for Somfy RTS

[b_weijenberg]

A new firmware version 227 for the RFXtrx433E is available on the RFXCOM download page.

Changes:
Some Somfy RTS motors did not respond correctly on up/down commands.
The maximum number of simulated RTS remotes is increased from 16 to 30.
Change angle commands for venetian blinds added.

Other changes:
Viking checksum added
Conrad RSL improved
BTHR968 forecast corrected
RTHN318 corrected
DM10 corrected
LightwaveRF Off corrected
Prego P-8426 sensor added
Kambrook, Rubicson and Viking supported in EXT firmware.