AirSpy Firmware version v1.0.0-rc5

Modifications for rc5:

• Enhanced the tuning resolution by 4x and the filter shape of the R820T2.
  • The average tuning delta is now 3.209843 Hz between 100 and 200MHz.
• Support of automatic lock on the External Clock Input at start up.
  • The clock must be 10MHz 3.3V CMOS Square or Sin.
• Cleanup, no functional changes (mainly replacing airspy_samplerate_t enum by uint32_t).
• MD5 for https://github.com/airspy/firmware/releases/tag/v1.0.0-rc5 (build on 2015-05-20):
  md5sum airspy_fw/airspy_rom_to_ram/airspy_rom_to_ram.bin
8312a36b5b7e1b276061a12049bc37a9 airspy_fw/airspy_rom_to_ram/airspy_rom_to_ram.bin
airspy_fw/airspy_rom_to_ram/airspy_rom_to_ram.bin Size 18 084 bytes

Note:
- This firmware support only 10MSPS & 2.5MSPS.
- Becareful if you build it yourself the `date` of the day is included in `airspy_rom_to_ram.bin`, 
so if you want to have same MD5 you need to change your PC date to 2015-05-20 just before to build it.

• To flash the latest firmware in attachment airspy_fw_v1.0.0-rc5.zip
• For Windows:
  • 1. Extract the archive
  • 2. Connect AirSpy with USB to your computer
  • 3. Launch airspy_spiflash.bat from extracted archive directory
  • 4. Disconnect AirSpy from USB computer
  • 5. Connect AirSpy with USB to your computer, now you can use your favorite software