Some features added (get_symbol, file, download)

[drizzi-novalabs]

For my purposes (a HW testing system) I need to load an ELF file and download it to the target (via OpenOCD + GDB), so I have added the required code to Avatar2.

So I have added:

• Target.get_symbol to get the address of a symbol
• Target.file/GDBProtocol.file to load the ELF file (-file-exec-and-symbols GDB command)
• Target.download/GDBProtocol.download to download the FW to the device (-target-download GDB command)

[mariusmue]

Hi there! Thanks for the contribution, looks very good to me!

Would you mind to do some "aesthetic" changes before we mainline in?
More specifically:

• Rename the method file to set_file and the watchmen from File to TargetSetFile
• Sanitize inside the methods in target.py whether the protocol supports the set_file and download feature, as only the GDBProtocol supports it as of now and provide an error message otherwise. (A simple hasattr() would be enough)
• Change the docstring for download (it has the one from exec) in target.py

Thank you again,
Marius

[mariusmue]

Perfect, added to mainline, thanks!