Firmware SW00750-2.6.0.42 release notes

Supported devices:
Z-UMTS, Z-UMTS (HW2)

News and fix:
- Added support for U64 S64 F64 variables
- Pump rotation support
- Support for Retain Variables
- In the notifications / alarms it is now possible to insert the value of a tag (print format)
- Added support for functions with U64 / S64 / F64 variables
- Auto APN enable
- GPS enabled [HW2]
- Various bufix solved