Using 'string' of hexcodes to generate encryption key.
Moved encryption key manipulations to parameters code
Added code to write encryption key to flash
Added feature_encryption to determine when to run init and other encryption code
Added code to allow ATE? and ATE=
Update at header to allow commands up to 36 characters (to allow 32character encryption codes)
     NOTE: Had to change from __pdata to __xdata because not space in PSEG
* Added checks to see what CPU is being used ...so encryptioncode is ompiled
and liked in the rfd900u variant.
Using function to determine effective encryption level (rather than if encryption is just initialised) to determine
if to proceed with executing encryption code

Included encryption and decryption in the code

Updated tdm.c to take into account increased size of data if encryption is to be used.

Much more work to be done.
* Clean up of code
* Updating trailer.window to be more accurate estimate of time left in window
Cleaning up code
Merge pull request #5 from joeman155/AES-wip

Aes wip