Fix #21 KeyError: 'minopsz'

[dmknght]

New version of radare2 changed minopsz and maxopsz to core (old: bin). This commit fixes the task failed when user submit a binary. Cred to @AlbertoFDR for minopsz fix and @xchaoinfo for r2pipe open

[dmknght]

p/s: Tested on my system and LiSa works perfectly with this fix

[danielpoliakov]

Hi, great work, thank you for all your commits.
As the pull requests deals with minopsz radare2 issue, I'd rather handle the remaining (pep8, typos, yara) in separate pull request.

[dmknght]

Hi, great work, thank you for all your commits. As the pull requests deals with minopsz radare2 issue, I'd rather handle the remaining (pep8, typos, yara) in separate pull request.

Ooops. I created the PR for the fix only and then i tried working on yara for my personal purpose and all commits were merged to here. Damn let me see if i can remove them

[EvilWatermelon]

Both values do not exist by default and if there is no value at both of them then Lisa will return a KeyError