microFS problems on version 2.1.0 beta

[rhubarbdog]

i am now using version 2.1.0 beta of microbit.hex which i flash using file copy. how ever now that i have to use microFS to to copy my program and class definition i am experiencing a lot of failures with the error message Expecting 2 values to unpack, only found 1
i believe this is in relation to outstanding file system issues and not a problem with microFS.

[carlosperate]

This is an issue with microFS, this PR aims to fix it, but still needs some tests added before we can merge:

• When reading a file, byte strings can use single and double quotes. #39

You can use it to patch your local installation of microFs, or if you like you can pip install -e . from that fork branch.